95 (USA)
50 (UK)
$2
£1
Number 5
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incla
The magazine for S
— E pa | an
ROM-PAC APPLICATIONS HAS
PROGRAMS ON PLUG-ON ROM
CARTRIDGES FOR THE ZX-81
"EDUCATIONAL PROGRAMS
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MORE TS1000/ZX81 SOFTWARE FROM...
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(212) 685-2080 M/C & VISA ACCEPTED
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FILL e DRAW/UNDRAW e FOREGROUND ON/OFF
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KAYDE Electronic Systems
ZX80/1
ZX KEYBOARD WITH
REPEAT KEY
Fully cased keyboard ........ $75.90
Uncased keyboard ....... ...... $55.90 4
Keyboard Case................... $21.90
This is a highly professional keyboard using executive buttons as found on top quality
computers. It has a repeat key and comes complete in its own luxury case. This is a
genuine professional keyboard and should not be confused with toy keyboards currently
available on the market
The 16K RAMPACK simply plugs straight into the user port at the rear of your computer. It is fully
compatible with all accessories and needs no extra power and therefore it will run quite happily on your $59.
Sinclair power supply. It does not over-heat and will not lose memory at all. As you may know. some 90
makes go down to 11K after being on for a while.
This 16K RAMPACK is very stable and will not wobble or cause you to lose your programme. It comes
fully built and tested with a complete money-back Guarantee.
KAYDE FLEXIBLE RIBBON CONNECTOR
Stops movement of RAM PACK and other accessories
(Not needed with a KAYDE RAMPACK) $25.9, 7
KAYDE 4K GRAPHICS BOARD MATES
The KAYDE Graphics Board is probably our best accessory yet. It fits neatly inside your ZX81. It
comes complete with a pre-programmed 2K Graphics ROM. This will give nearly 450 extra graphics
and with the inverse makes a total of over nine hundred. $59.
The KAYDE Graphics Board has facilities for either 2K of RAM (for user definable graphics), 4K of ROM 90
or our 4K Tool Kit Chips that will be available shortly All the graphics are completely software
controlled, therefore they can be written into your programmes. Here are a few examples: A full set of
space invaders -— Puckman — Bullets, Bombs — Tanks — Laser Bases and Alien Ships.
NO EXTRA POWER NEEDED
KAYDE 16K GRAPHICS BOARD SOFTWARE ima
PECKMAN: The only true ZX version of the popular arcade game. - S $7
Centipede: “In all | think this is the best presented moving graphics program I've yet seen." Phil Garratt. 1-90
Interface.
SPACE INVADERS: The best version available anywhere. Graphics software can only be used with a graphics board
Centipede: ‘‘In all | think this is the best presented moving graphics program I've yet seen.” Phil Garratt, $7 7-9
Interface. 0
3D/3D Labyrinth: A Cubit Maze that has corridors which may go left, right, up, down. Peckman (the
latest addition in 81 games).
WHY WAIT TO PAY MORE — Le zu a pe NS pus PE ve EE EN!
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FAST, IMMEDIATE DELIVERY E Puadbdend me M pam 16K RAMPACKS $59-90 each i
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Tel: 0493 57867 (Dept. SY1) p wem {
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Please pay by ! i
International money order or certified i
cheque for immediate delivery. | Please add $5 p&p for all hardware and $2 for all software. Please make l
cheques payable to Kayde Electronic Systems Ltd.
| un mon mm oe due e map ads wen Ae de «e Ken mm mb cm uml
The magazine for Sinclair users
Ei (| n
September/October 1982
Volume 2, Number 5
DEPARTMENTS
A O OL e GN es wets ee gS
A NA
8D eYNCNOlOR. 0 o ea Grosjean
DE SURV AO deci. Klyver, Kluth, Laska
20 Siist tor Fun. |... a ik oes Dewhurst, Hampson
2A Porcopllons o n esti cie eR Ornstein
The ZX Parser and the Operations Routines
88 HardwareTips......... oes Chaiet
MicroAce Hardware Peculiarities
Qo oue rS a A SM OSA Wo FILIAL duse yd
96 Index to Advertisers........... sse nnn nnn
SYNC IN THE CLASSROOM
29 List Learning with the ZX81............. Hollandsworth
A program for memorizing lists
34 Teaching with the ZX81....................... Deeson
An overview of the British scene
42 MapsandtheZX80/81........................ Doakes
Rethinking maps and mazes
50 HowManyBlocks..........oeeen nnne Kelly
A program for preschoolers
BE suae. 2s t aida aa coa Pi ABE UNA Klyver
Developing math and strategy skills
55 Arithmetic with a Smile....................... Repicky
A tool for elementary math drills
56 Arithmetic series......................... Van Workum
Developing math concepts through series
58 Solving Implicit Functions.................. Wentworth
Working with equations; algebra help
62 BOLEX: Beginner's Ohm's Law EXercises. ...... Stadta
Help for general science and physics
HARDWARE
66 Repeat Key Option.............occoococococcccooo Ingle
Build your own repeat key
MATH
68 Degrees, Grads, and Radians. ... . Rig caper od aE Lam
Conversion programs
69 Rounding Off and Conditional Tests........... Stauffer
Pythagorean triples
MACHINE LANGUAGE
TO Block Transfers...................... AUR, CUPS: Scher
Machine language programming technique
GAMES
TE. Chad «4 E a A peo. RETE E MAI Yu
Pit your survival skills against the robot warriors
TO AO DIE e ELLOS IA ii S ad ONE Dewhurst
To the Spaceport, fast
80 HouseofHorrors.................e eese Duchene
One for Halloween
85 Moum 4. eese dues aa RS NON. Day
Random wit and wisdom for your next party
90 8K ROM Updates. ..... Ahl, Horton, McGath, McLauglin
Nicomachus, Castle Doors, Widget, Hurkle
REVIEWS
78 The Complete Sinclair ZX81 Basic Course . .. Blechman
Book review
79 ZX81 Chess vs. ZX Chess II. ............... Wren-Hilton
Software review
in ————— ———————————— UGOos AAÁXLZZX
PR IR EI LL IE SEE DT LE IES EE REE ENTE TO ED EE SEE
Staff
Publisher/Editor-in-Chief.............................David H. Ahl
Manan A EN SOS MENORES. Paul Grosjean
te o o A LAS IA e CI AN David Ornstein
UR Correspondent. sevo See eS AR Martin Wren-Hilton
A E A A A E o Elizabeth Magin
O rl IN ER a ete IAN RM ao Susan Gendzwil
Assistant Art Director..........................-Diana Negri Rudio
Toncsc He I E RA hy ER A A QS EI S Se Karen Brown
Renea Cole
Financial Coordination dr ss De mrt William L. Baumann
Personne kand Finance. Wo La eek es Fee an Patricia Kennelly
e TA nen ls qe iai ve ik we E Frances Miskovich
Carol Vita
a SalesManager AN E oe DORIA Jim Beloff
MEMBER
Volume 2, Number 5
SYNC (USPS: 585-490; ISSN: 0279-5701) is published bi-monthly by
Ahl Computing, Inc., a subsidiary of Ziff-Davis Publishing Company.
David Ahl, President; Elizabeth B. Staples, Vice-President; Selwyn
Taubman, Treasurer; Bertram A. Abrams, Secretary. 39 E. Hanover
Ave., Morris Plains, NJ 07950. Second class postage paid at New York,
NY 10001 and at additional mailing offices.
Subscription rates: USA: One year (6 issues), $16; two years (12 issues),
$30; three years (18 issues), $42. Canada: $3 per year additional. Other
foreign: $5 per year additional.
For SYNC advertising information, contact Jim Beloff, SYNC Adver-
tising Sales Manager, Ziff-Davis Publishing Company, One Park Ave.,
New York, NY 10016 (phone: 212/725-4216).
All other correspondence should be addressed to: SYNC, 39 E. Hanover
Ave., Morris Plains, NJ 07950. In U.K., SYNC, 27 Andrew Close, Stoke
Golding, Nuneaton CV 13 6EL.
Postmaster: Send address changes to SYNC, PO Box 789-M, Morristown,
NJ 07960.
Cover photo and other photos of the Sinclair computer and the children courtesy of Donna Compton.
September/October 1982
data-assette®
SOFTWARE “Sippie”
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MAZOGS
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difficulty. only $29.95 16K .
GALAXIONS
Features of an arcade game. Attacks-Defends and keeps personal scores. only $14.95 16K
BATTLE SHIP
Play against the computer to destroy its battle ships, cruisers, destroyers, etc. only 10.95 16K
VOLCANIC DUNGEON/HANGMAN
1. Attempt to rescue the elfin princess; mystical monsters, pits, fireyheavens. Reducing strength and water make the quest anything but easy.
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ALIEN INTRUDER/HIEROGLYPHICS
1. You find you are the only survivor on the Explorer Class Ill star ship. Try and escape before you fall victim to the alien monstrosity that
destroyed the crew.
2. Decode the ancient 39 symbol alphabet in time to save a famous explorer. only $10.25 16K
WUMPUS ADVENTURE/MOVIE MOGUL
1. 1-4 players seek the famous creature in the most famous and dangerous Wumpus hunt ever.
Features: Super Bats, Pits, Tremors, Swamps, Magic Arrows, Giant Sea Serpents, Wumpus Muk and Magic Springs.
2. Guide making you through the often hilarious traumas of production. Use your budget wisely to make a fortune. only $10.25 16K
GREAT UNCLE ARBUTHNOT'S INHERITANCE
You are left $100,000 but first must turn $100,000 of it into a further $100,000 by investing in the British Stock Market and Metal Exchange in
26 weeks. You then have a further 26 weeks to make $100,000 running a soft drink factory. only $10.25 16K
GREAT BRITAIN LTD.
You are the Prime Minister and Chancellor of the Exchequer of Great Britian. Your aim is to stay in office as long as possible. $10.25 16K
AROUND EUROPE IN 80 HOURS
You have a bet of $20,000 to visit 12 capital cities in Europe in two and a half days, travel agents permitting. only $70.25 16K
HOME-SAVINGS EDUCATIONAL - Learn
FINANCE | CHESS]
Balance and maintain checkbook. No overdrawn or returned checks.
only $9.95 16K Six levels and analysis options. only $12.95 1K
DATES > CHESS II
Keep your diary in order. only $8.50 16K Seven levels and a recommended move option. only $24.95 216K
HOME PLAN
Keep track of your food and freezer needs. only $9.95 16K ZX-BUG
30 in 1 tool. Disassemble. Access all registers, search, modify memory
APPLICATION PROG RAMS with cassette routines. only $14.95 16K
TOOL KIT
Provides many special features (line number, search and replace, d
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only $10.25 16K 7X-99 TEXT
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Coming in the next issue: HIGH RESOLUTION GRAPHICS BOARD AND COLOR All for your ZX-81/Timex 1000
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lBcters
ROMs and RAMs
Dear Editor:
Could you please put more programs
for the ZX80 with the 8K ROM in SYNC?
All I notice is programs mainly for the
ZX80 with the original 4k ROM and the
ZX81.
Cris Bottjer
RR #2, Box 86-A 500 E.
Kendallville, IN 46755
Ed.—See “ROMs and RAMs” in SYNC
Notes in this issue.
Memory Saving Tips
Dear Editor:
I want to call the attention of SYNC
readers to the second paragraph on p.
129 of the 8K ROM manual: “A numerical
constant in the program is followed by its
binary form, using the character CHR$
126 followed by five bytes for the number
itself.” This is a very inefficient way to
store numbers.
Dr. lan Logan in SYNC 2:2 showed
some good ways to get around this ineffi-
ciency by using SGN PI and NOT PI for 1
and 0. He also used VAL “number” which
saves three bytes. I suggest using one
letter variables to hold numerical con-
stants if you use the same constants more
than once, or, if you use numbers that are
more than four digits long. Declare these
variables from the command mode so that
they do not occupy program space.
Another way to save memory is to use
GOTO CODE “C” instead of GOTO VAL
"40". A byte saved is a byte earned. This
same technique could be used for any
number between 10 and 255 even though
6
MS
¿120 IF Ig4="
not all these characters can be accessed
from the keyboard. Consider the follow-
ing line:
500 LET N=N/100
Y ou can accomplish the same thing with:
1 LET N=N/CODE “N”
POKE 16520,100
After these lines are entered, line 1 will
look like:
1 LET N=N/CODE “?”
Now all you have to do is EDIT and
renumber the line to 500. If you want to
do several lines this way, type your pro-
gram from the highest line number to the
lowest so that the line you just typed will
always be the first line in memory.
John Coffey
PO Box 448
Scottsburg, IN 47170
Dear Editor:
Concerning Gary Chandler's “Alien
Treasure” in SYNC 2:4, there are several
ways to increase the efficiency and speed
of the program.
First, the four lines which check the
bounds (132-135) can be deleted if logic is
used:
S23 LET IS-INKEYS
2 ge gr NOT Ig¢="" THEN PRINT AT
"81 Te THEN GOTO 53
35 "^ THEN LET @=INT tf
“ THEN LET EzE-IB5:£-—
' THEN LET B=D+1B:<3
" TREN LET AA+ IAS
"^" THEN LET A=A-1A>1
ig=
IPIE
ND p22)
TOCO EF AY
¿100 IF I$-
110 IF I$z"
J O »dge:
If the expression in parentheses is true,
it has a value of one; otherwise the var-
lable is not changed. Also, INKEY$
could change between lines; therefore it
is always best to assign INKEY$ to a
variable and then check it as in the
example above.
Second, lines 81-84 indicate which
direction the monster is to move. This
can best be done by using SGN. Delete
lines 81 and 83, and then enter:
82 LET X=X+SGN(A-X)
84 LET Y=Y+SGN(B-Y)
SGN returns -1 if the expression in paren-
theses is negative, 1, if positive, and 0
otherwise. Then the variables X1 and Y1
can be deleted by deleting lines 7, 8, 86,
and 87.
Third, if the inspiration is great enough,
the array can be deleted and a PEEK can
be done to the screen location desired.
Use
LET S$=CHR$ PEEK (PEEK 163964
256 * PEEK 16397+33* R+C+1)
where R is the row and C is the column.
The character at that position is returned
in S$.
Michael Williams
1300 DePaul Way
Virginia Beach, VA 23464
The SAVE Signal
Dear Editor:
A friend recently purchased Sinclair’s
16K RAM pack, but found that the SAVE
signal was drowned out by the extra noise
it caused. After trying several types of
filtering, I found two large foil tabs on the
underside, one by the edge connector
and the other next to the regulator.
Connecting these with wire and rosin core
solder reduced the resistance and the
noise.
Raymond Fowkes
PO Box 336
Coalinga, CA 93210 Fa
SYNC Magazine
Has Down Time
Got You Down?
MicroSync
Has The Answer
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To Purchase a Maintenance Agreement Use the Coupon Below.
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(] | Would Like to Purchase a MicroSync Maintenance
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My check or money order is enclosed.
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OL) sane a Mi O
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Phone ( )
Pseudo-Glitchoidz
From time to time readers call our
attention to “Glitchoidz” they have met
in entering programs. However, on closer
examination we find that these are
“pseudo-Glitchoidz” because the problem
is not in the listing. You can avoid these
“pseudo-Glitchoidz” by paying close at-
tention to the following suggestions:
1) Before starting to enter a program,
note the ROM requirements as shown in
the upper right or left corner of the first
page of the article. A 4K ROM program
is for a ZX80 or MicroAce; an 8K ROM
program is for the upgraded ZX80 or
MicroAce, the ZX81, and the Timex/
Sinclair 1000. You cannot enter a 4K
ROM program on an 8K ROM machine
or vice versa without translation. This
seems to be the most common problem
new users encounter. Wherever possible
we give both listings. Usually 4K ROM
programs can be translated to the 8K
ROM, but the reverse is often difficult.
2) Pay careful attention to the RAM
requirements before you start typing in
the listing.
3) Read the article through carefully
before attempting to enter the program.
While we can sympathize with our
readers' eagerness to try out the new
programs, we remind everyone that the
Glifchoidz Report
article and that the article contains nec-
essary information about the program.
4) Enter the program as printed in the
listing taking into account any directions
given in the article. Be sure you know
what the program is supposed to do. If
the program does not run, assume first
that an entry error has been made and
double check your entry. All the 8K ROM
programs which look like the listing for
“List Learning with the ZX81" in this issue
are direct printouts from our ZX81. The
program was entered on it, tested (and
found to work as the author indicated),
and then printed out directly from the
computer with no intermediate typing
stage. This does not mean that the pro-
gram has no bugs, but the listing printed
did run without bugs during the time we
tested it. Occasionally some characters
are not as clear as we would like due to
the reproduction process, but the com-
puter will tell you if this results in a syntax
error while some experimentation may
help locate the correct entry in other
—— A ANS ES AND ARE E E i E A Ad AAA AAA
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(806) 376-5723
SYNC Magazine
E
>. >.
AO anane a EENE Eo — — MA <i par URE RR, “SS.
BEHIND EVERY
GOOD SINCLAIR
If you own a Timex-Sinclair 1000 or
ZX81 computer, you should have a
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Mail to: Memotech Corporation, 7550 West Yale Ave.
Code: SYCO-9-10
nver, 0 80227 | |
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*Price Qty. Total
| 64K RAM $179.95 |
| 32K RAM 109.95 |
| 16K RAM 59.95 |
| Centronics Parallel Printer Interface 104.95 |
| RS232 Printer Interface 139.95 |
High Resolution Graphics 144.95 |
| Shipping and handling 4.95 $4.95 |
à * All prices quoted in U.S. dollars Tax**
** Colorado residents please add sales tax Total l
H Check (J MasterCard [] Visa |
ee Node O de oe Cae o TENE. |
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: Name i
i Address
| City State Zip 1
Memopak 64K RAM The 64K RAM extends the
memory of your Sinclair by 56K to a full 64K. It
is directly addressable, user transparent, is
neither switched nor paged and accepts such
BASIC commands as 10 DIM A (9000). The
Memopak 64K turns your Sinclair into a
powerful computer suitable for business,
recreational and educational use. No additional
power supply is required.
Memopak 32K RAM The 32K RAM Memopak
offers your Sinclair a full 32K of directly
addressable RAM. Like the 64K Memopak, it is
neither switched nor paged and enables you to
execute sophisticated programs and store large
data bases. It is also fully compatible with
Sinclair's or Memotech's 16K RAM to give you a
full 48K of RAM.
Memopak 16K RAM The Memopak 16K RAM
provides an economical way to increase the
capabilities of your Sinclair. And at the same
time, it enables you to continue to add on other
features with its “piggy back" connectors. It is
compatible with the Sinclair 16K or a second
Memopak 16K or Memopak 32K to give 32K or
48K of RAM respectively.
Memopak High Resolution Graphics The
Memopak HRG contains a 2K EPROM monitor
and is fully programmable for high resolution
graphics. The HRG provides for up to 192 by 248
pixel resolution.
Memopak Printer Interface The Memopak
Centronics Parallel or RS232 Interface
paks enable your Sinclair to use a wide range of
compatible printers (major manufacturers’
printers available through Memotech at
significant savings). The resident software in the
units gives the ASCII set of characters. Both
Memopak printer interfaces provide lower case
character capabilities. The RS232 Interface is
also compatible with modems.
New products coming soon Memotech will
soon be introducing four new Sinclair
compatible products: a high quality, direct
connection keyboard, a digitizing tablet, a 16K
EPROM and a disk drive. Watch for our future
advertisements.
SYNC Program Listings
. Readers should note the following
conventions used in the program listings
in this issue:
| The ROM and RAM requirements for
running a given program are shown in the
upper outer corner of the first page of an
article. Observe these carefully.
_ NEWLINE and ENTER are used inter-
changeably. :
to show the type: b for binary; d for
decimal; h for hexadecimal.
. In PRINT statements:
++: Enter a necessary space.
. A (32): Use the graphic character on
the A key 32 times. The underline means
get the graphic on the key given in the
line by whatever way your machine uses
to get the graphic. An overline means use
the letter in inverse form, e.g., A.
. INPUT: An underlined word found on
the keyboard should be entered from the
keyboard, not spelled out. If the keyword
will not enter, hit THEN, the keyword
you want, backspace and delete THEN,
continue entering the line. This memory
saving technique may be disregarded if
you have enough RAM.
ee aaaaaaaaaaaaasassssssssssssssssssssħÃĂÅ
aaa
gl
A number may be followed by a letter|
cases. The 4K ROM programs, however,
are not direct printouts so there is the
possibility of an error in these listings.
5) Do not attempt to make changes ina
program which does work before you
understand the program as written. Again,
remember the author is trying to show
you something.
6) Be sure you know whether a given
word in the program is a keyword, that is,
a word entered from the keyboard in one
stroke, or a word that must be spelled
letter by letter. If a keyword is used within
the quotation marks in a print statement,
it does not function as a command but as
the word in its normal meaning. This is a
memory saving technique which can be
ignored if you have the additional
memory.
An Alternative Display Method. 2:3.
Space Warp. 2:3.
These programs are for machines with
the 4K ROM. The problems reported by
some readers stem from trying to enter
these programs on the ZX81. So the
solution is quite simple: Do not attempt
to enter a 4K ROM program on an 8K
ROM machine or vice versa.
DEF. 2:4
Listing 3: Change line 110 to:
110 DIM F$(5,17)
The program will work in 2K.
ZX Destroyer. 2:4, pp. 49-50.
The author has called the following to
our attention:
1) Both the 4K and 8K versions can run
on as little as 2K RAM.
2) Figure 4: Line 150: Delete the set of
quotation marks after the comma.
3) Figure 5: Line 20 could read PRINT
“ZX DESTROYER”. |
4) Figure 6: I REM, 6th line down, last
character. This is a U, not a W asit might
appear.
5) Figure 8: Delete lines 10-35.
Renumbering by a USR Routine. 2:3, p.
12.
The author notes a minor correction
and a possible problem.
1) The quotation marks between TAB
and RND in both cases are inverse.
2) The E between V and 7 may have to
be changed to 3 on some ROMs. The
manual ZX8/1 BASIC Programming (1st
ed., 1980) shows the same character for
codes 7 and 135. The 135 is in error; it is
the inverse of 7. Ed-Both E and 3 work
on our ZXól. Fg
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10
SYNC Magazine
SINCLAIR/TIMEX USERS
NOW SYNERGISTIC OFFERS YOU THE 'SMART"” CHOICE
DESIGN
THE SYSTEM LOGIC KBD-I
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e SMART" shift function
e Tactile feedback : :
+ 59 keys (with left and right shifts) Contact resistance: 200 @ 1mA
e Standard (QWERTY) typewriter format Contact rating: 1.0V/A
e Silk screen labels compatible with
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e Compact design a :
e Rugged yet attractive black anodized Switch life: 5.0x10° operations
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MAIL ORDER TO:
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Sync notes
SYNC in the Classroom
In the wake of the recent federal
budget cuts in education S YNC has been
receiving inquiries from teachers and
school administrators about the Sinclair
computer. The question they ask most
frequently concerns the Sinclair as an
alternative to the larger popular computer
systems. They are interested in the fact
that for the price of one of the popular
systems they can get several Sinclair
computers with 16K RAM packs and
provide hands-on experience to several
students instead of just one. For the price
of several large computers a whole class
could be equipped with the Sinclair com-
puter. So a school system even with sharp
budgetary constraints does not have to
cut back on basic computer literacy
programs; it could even initiate such pro-
grams.
Paul Grosjean
Another question they often ask con-
cerns the availability of educational soft-
ware. Since the ZX80 and ZX81 were
introduced to the United Kingdom mar-
ket some months before they were avail-
able here, most of the educational soft-
ware available is from U.K. sources. Some
U.S. software suppliers have made
arrangements to distribute U.K. software
here.
SYNC has received a number of articles
which suggest some of the educational
uses of the Sinclair computers, and we
have gathered some of these for our
theme section “SYNC in the Classroom.”
These articles deal with a variety of levels
from pre-school up.
Two major characteristics show up in
the articles we have received. First, the
main focus of most is math. Perhaps this
is natural; after all, a computer does
compute. We will be using some of these
in future issues. Second, many articles
use the computer as a substitute for a
pencil and scratch paper. Certainly this is
one use, and it is an important one where
the computations are extremely lengthy
and tedious. However, it seems hardly
worth the trouble to load a tape to do
something that a pencil and paper will do
more quickly. Since such programs are
not difficult to write, they tend to appear
first.
At the present the computer seems to
be more of a novelty in the classroom
than an integral tool in the learning
process. There are three main obstacles
to classroom computer use. First, the most
serious obstacle is that we do not yet
have enough teachers with computer
training to use the computer as a teaching
tool. It seems frequently that the com-
puter is assigned to the math department
which is expected to either have or get
the expertise to use it. Like other equip-
ment which requires some study and work
to use the computer may be in danger of
being relegated to the closet when the
enthusiasm of the administration for
getting on the computer bandwagon
wears off.
GAMES PACK
Beat this for value! Five 16K programs
Plus two 1K programs
3-D Battle (M/code - 1K)
City Bomb (M ‘code - 1K) value.
Warp Wars (Basic & M ‘code - 16K)
Snake (Basic 16K)
Sweet Tooth (Basic & M'code - 16K)
Slalom (Basic 16K)
Black Holes (Basic 16K)
ALL ON ONE CASSETTE FOR
ONLY $9.90 (£4.95)
character as you require.
before.
Fill - fills your screen instantly with your specified character
Reverse - changes each character on your screen to its
(16K - ZX81)
First computer version of this popular
game of strategy and tactics. Both
grids on view together. Establish the
position of your fleet then locate and
destroy the computer's fleet. Visual
display shows hits and misses made
and gives running score.
ONL Y $9.90 (£4.95)
inverse video.
achievement!!
RY GRAPHICS TOOLKIT ¿eau tomes! ^^ (zx81- 16K RAM ONLY)
22 exciting MACHINE CODE routines that give you control over your screen as never before!
Onscreen/Offscreen turns your screen on or off.
Background On/Off Fills your screen by your
h : specified character. When foreground is on existing
shapes as you like and draw or undraw each at will information is unaffected and shapes will appear to
pass in front of your background, without deleting it
Search and Replace will search the screen for
every occurrence of the character you specify and
Draw/Undraw draws or deletes your multi-
character shape which is defined in a REM
statement, You may define as many different
at whichever screen position you choose.
Foreground On/Off use this to 'protect' existing
characters on your screen. When on new shapes
An Essential addition to your 16K RAM ZX81
TOOLKIT (written by Paul Holmes)
Provides the following additional facilities:-
Line renumber - you state starting number and increment
GOTO's and GOSUB’s included in line renumber.
Search and List - Searches for and lists every line
containing specified character.
Search and replace - changes every occurance of a
Free space - tells you how many free bytes you have left
SPECIAL GRAPHICS ROUTINES
Hyper graphics mode -graphics never seen on a ZX81
TAPE ROUTINE - provides a system WAIT condition
until a signal is received in the cassette ear jack.
All these routines are written in machine code and together
take up only 1K of your precious RAM - an incredible
FOR 16K ONLY $9.90 (£4.95)
ptm e em em em em 22222 HÀ em am A Uu m M — — a a —— easy
THE EXPLORER'S
GUIDE TO THE
ZX81
If you have ZX81 then you need this
book (120 Pages).
1K and 16K Programs.
Games and Application.
RAM and I/O Circuits.
Programming Hints
$11 from:
will appear to slide behind and re-emerge from
other shapes.
Border/Unborder Draws a border round the edges
of your screen area. Edit lines can be used if required.
Your border is protected when foreground is on.
Fill Fills any number of lines you specify, starting at
any line you specify, by your chosen character.
Reverse Converts all characters to their inverse
video, control as in FILL.
Print Position Controls
UP, DOWN, LEFT, RIGHT - alter your next PRINT
position in the direetion indicated
Editprint Moves next PRINT position to first edit line.
Scroll facilities
UPSCROLL, DOWNSCROLL, RIGHTSCROLL,
LEFTSCROLL - Scroll your screen in the direction
indicated
replace it with your new character.
Square draws a square or rectangle from your
specified co-ordinates.
All these routines are in machine code for SUPER
FAST response! Simply load GRAPHICS
TOOLKIT, which repositions itself at the end of
your RAM, and then your own program (or key in a
new one), GRAPHICS TOOLKIT uses only 2K of
your RAM and that includes space to load the
programmers TOOLKIT described above.
ALL FOR ONLY $11.90 (£5.95)
This includes a cassette with 2 copies of the
program, 2 copies of a demonstration program,
plus a comprehensive instruction booklet with
examples.
PLEASE NOTE ALL PRICES ARE FULLY INCLUSIVE AND ARE APPLICABLE FOR EXPORT. INCLUDING AIRMAIL POSTAGE
PAYMENT MAY BE MADE IN STERLING (MONEY ORDER AVAILABLE AT YOUR BANK) OR YOUR OWN U S.$ CHEQUE
MADE PAYABLE TO JRS SOFTWARE DESPATCH NORMALLY 7 DAYS FROM RECEIPT OF ORDER
19 WAYSIDE AVENUE, WORTHING, SUSSEX. BN13 3JU Telephone: (0903) 65691
TIMEDATA
3 - Waldon Road
Califon, N.J. 07830
Enclosed
Name
Address
Check/M.O.
Stato... An
SYNC Magazine
©
E
ROM Routines. |
pr AE TAE TA dd cbe laria vnde
|
$9
NEW!
From Intercomputer
A
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Of
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Education
And
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Software
for your ZX81 or Timex Sinclair 1000
Please send me a FREE
Program and Catalog
Name
Address
Send this coupon to:
Intercomputer
Box 90
Prudential Center
Boston, MA 02199
PLOT
ARCCOS ARCTAN
COPY CLEAR. CONT
: LN EXP AT
ARCSIN
SGN
C
ALS
V
Introducing the
Sinclair ZX81.
If you're ever
going to buy a personal
computer, now is the time
to do it.
The Sinclair ZX81
Is the most powerful, yet
easy-to-use computer
ever offered for any-
where near the price:
only $99.95* completely assembled.
Don't let the price fool you. The ZX81 has
just about everything you could ask for in a per-
sonal computer.
A breakthrough in personal computers.
The ZX81 is a major advance over the origi-
nal Sinclair ZX80 —the first personal computer to
break the price barrier at $200.
In fact, the ZX81's 8K extended BASIC offers
features found only on computers costing two or
three times as much.
Just look at what you get:
m Continuous display, including moving graphics
Sinclair technology is also available in Timex/Sinclair computers
under a license from Sinclair Research Ltd.
SCROLL NEXT
:
IN KEYS
E | of key words like PRINT,
RUN and LIST
m Automatic syntax error
m detection and easy editing
INPUT PRINT
POKE
BREAK
es
= Multi-dimensional
string and numerical arrays
m Mathematical and scien-
tific functions accurate to
8 decimal places
m Unique one-touch entry
m Randomize function
useful for both games and serious applications
= 1K of memory expandable to 16K
m A comprehensive programming guide and
operating manual
The ZX81 is also very convenient to use. It
hooks up to any television set to produce a clear
32-column by 24-line display. It comes with a
comprehensive programming guide and oper-
ating manual designed for both beginners and
experienced computer users. And you can use
a regular cassette recorder to store and
recall programs by name.
Order at no risk.**
We'll give you 10 days to try out the ZX81. If These numbers are for orders only. If you just
you're not completely satisfied, just return it to want information, please write: Sinclair Research
Sinclair Research and we'll give you a full refund. Ltd., 2 Sinclair Plaza, Nashua, NH 03061.
And If you have a problem with your 7X81 forge Suh and handling. Price includes connectors for TV and cassette, AC adaptor, and
send it to Sinclair Research within 90 days and "OUS app IU e
we'll repair or replace it at no charge.
Introducing the ZX81 kit.
If you really want to save money, and you
enjoy building electronic kits, you can order the
ZX81 in kit form for the incredible price of just
$79.95.* It's the same, full-featured computer,
only you put it together yourself. We'll send com-
plete, easy-to-follow instructions on how you can
assemble your ZX81 in just a few hours. All you
have to supply is the soldering iron.
A leader in microelectronics. And pe DARE d has bug riores
published pre-recorded pro- any powerful, full fledged com-
: The ZX81 represents the latest technology in grams on cassettes for your puter, the ZX81 is expandable.
microelectronics. More than 10,000 are sold : ZX81. We're constantly coming Sinclair's 16K memory module
every week. In fact, the ZX81 is the fastest selling out m o we'll pugs id Wan e
: send you our latest software your . Cost is $49.95, plus
personal computer in the world. catalog with your computer. shipping and handling.
We urge you to place your order for the
ZX81 today.
E a
ha — | | ol — ||
To order, simply call toll
free. Or use the coupon below.
Remember, you can tyitfr TO order call toll free: 800-543-3000
eee a Tne Serna am emi m m M AN M
start enjoying your own Price" Qty. — Amount
computer. [OM o 10 E |.
Call toll free 800-543-3000. Ew | 9 5. 0 eni oc
Ask for operator #509. [p 16K Memory Module | 4995| —
In Ohio call: 800-582-1364; | ShippingandHanding d 49s| | $495
in Canada call: 513-729-4300. To
Ask for operator #509. Phones
open 24 hours a day, 7 days
a week. Have your MasterCard
or VISA ready.
MAIL TO: Sinclair Research Ltd.,
One Sinclair Plaza, Nashua, NH 03061.
Name
Address
Cu OA)
*U.S. dollars
Second, some teachers are afraid of it
and will resist its use. This is partly
because some students are already far
ahead of them in computer mastery, and
we adults have a hard time accepting the
fact that an elementary school student
can know more than we do about a
subject that everyone knows is difficult to
master.
Third, some schools restrict the use of
their computers to advanced students.
This is unfortunate because the idea is
encouraged that computers are only for
“special” students, not for “ordinary”
students. Above all, the computer is not
integrated into the total school curriculum
as a tool with a contribution for each
area.
The serious use of the computer in
education depends upon having teachers
trained to use it in their particular fields,
software exploiting the computer's cap-
ability for interaction with the student,
and an openness to a new tool for teach-
ing and learning.
How is the computer being used in your
local school system?
ROMs and RAMs
Readers have requested that we publish
8K ROM translations of the programs we
published before the 8K ROM was intro-
duced. We are including some of these
translation in “8K ROM Updates” else-
were in this issue. We have also been
asked to publish programs for the ZX80
with the 8K ROM.
We specify the ROM and RAM require-
ments on all programs and articles where
these are necessary, but we do not specify
the machine as such.
The 4K ROM programs will work on
the ZX80 and the MicroAce; The 8K
ROM programs, on the ZX81 and the
ZX80 with the 8K ROM. However, since
the SLOW mode cannot be accessed on
the ZX80 with the 8K ROM, programs
which must be run in SLOW mode require
some slight modification. The SLOW
mode functions to allow the viewer to see
the display change. Usually the action
graphics routines have two basic parts: 1)
putting a new picture on the screen, and
2) taking it off. On the ZX80 with the 8K
ROM you can use a PAUSE between
these two parts to allow you to see the
change. For example,
10 LET J=1 Initialize
20 LET I=1 variables
30 PLOT I,J “Prints” picture
40 UNPLOT IJ Removes picture
50 LET J=J+1 Adjusts variables for
new picture
60 GOTO 30 Loop back to “print”
new picture
For the ZX80 with the 8K ROM you
would add
35 PAUSE (number, e.g., 10)
The number determines the length of the
PAUSE. In the U.S. 60 equals one second;
in the U.K. 50 equals one second.
Generally our authors write their pro-
grams on one specific machine. We
request our authors to supply the listings
or modifications necessary for the users
of the other ROMs and machines; on
occasion we modify or translate a pro-
gram. The ROM in parentheses indicates
such a translation or adaptation.
Since 8K ROM programs are virtually
identical we have not made separate
listings for the ZX80 users.
Some readers have also asked concern-
ing the RAM designations. These RAM
designations (usually in the upper right or
left corner of the first page of an article)
do not refer to the length of the program,
but to the amount of RAM your machine
must have to run the program. Many
programs designated 16K require much
less than 16K RAM, but, since most users
and authors have 1K, 2K or 16K RAM,
we do not specify intermediate RAM
levels. When a RAM designation appears
in parentheses, we mean that modifica-
tions of the basic program are provided
for use with that much RAM. "n
Get on the Control Bus
for only $49.95 “ni
. -- and be on TIME.
With our real Time Clock and Calendar
Compatible with ZX80 /81
TIME MONTH DATE YEAR DAY OF WEEK
23:59:59 («Top ca eoa er "uu EE
€ Leap year correction
e 12/24 hour format
O + 30 second time correction
(hardware or software)
€ Battery back-up circuit
Comes complete with:
€ All software needed to operate clock and
Input/Output ports
€ On board 5 volt regulator.
€ Feed through Sinclair Bus connector
to allow normal expansion.
€ Each port is expandable through Multiplexing.
€ /O ports and other controls mate with Radio Shack”
44 pin edge socket.
€ 90 day Warranty
Accessories used with 1/O Board:
€ A to D and D to A converter
€ Wireless control system compatible with BSR”
modules
0 Solid state 25 amp switch modules
€ 8 SPDT 5 amp relay card
Future products used with 1/0 board:
0 Touch Tone" encoder/decoder and
other telephone products
€ Speech synthesizer
€ Sound synthesizer
8 lines departing
(outputs capable of driving relays)
8 lines arriving
(T T L compatible inputs)
MicroAce & TIMEX” 1000
> All accessories can be connected together
and separately controlled from the 1/0 parts
A to D and D to A converter (Built and tested)
Bare Ato Dand Dto A board and manual
Wireless control system (Built and tested)
Solid State” AC switch (Built and tested)
Relay board (Built and tested)
317] Clock IC and crystal (Tested)
NEL Shipping and handiling
Orders accepted by phone or mail.
California residents add 696 tax
For mail orders, send check or money order.
Foreign orders must be in U.S. currency.
write for free catalog
oR AUDIO
P.O. Box 3295
Escondido, CA 92025-0580
Information (714) 741-5132
24 HOUR ORDER LINE
NAT. 800-227-1617
| MasterCard |
Calif. Res. 800-772-3545
Ask for operator 367
Make Your Sinclair
Work Harder, Better...
with quality, affordable and dependable
peripherals from CAI.
The Interface
The CAI/ O Board? plugs into the
computer's expansion port and is the
interface that lets your computer
communicate with the outside world.
There is a serial RS-232 compatible I/ O
port, 3 parallel I/ O ports used to design
circuits to control home lights, power
relays and additional ports to accept
printer, mass storage device and memory
expansion.
95 95
$79 when 36995. purchased
with CAI peripherals
purchased separately
The Printer
New! The CAI/ P40 prints the complete
library of regular and inverse alpha-numerics
and graphics in 40-column width. Three
enhanced (double type size): List program
from memory, print text or data from
$ 95 complete stand alone printer. (can
139 be upgraded to use with other CAI
peripherals)
$ 1 19” compatibility with other CAI
peripherals
CAI introduces the Stringy Floppy® for
the Sinclair or Timex Sinclair. It has the
price. Data is stored on an inexpensive
continuous loop magnetic tape cassette.
incredible 14,000 baud - - 56 times faster
than Sinclair cassette recorder interface.
two Stringy Floppy drives for even more
versatility.
user-addressable modes print in regular or
program, print screen
requires CAI/ 0 Board for complete
Mass Storage Device
speed of a disc drive at a fraction of the
This device inputs and outputs data at an
The system is designed to accommodate
1099 autres CANO Boar
Computer Network
Package
This package consists of ASCII
conversion program, phone modem,
connecting cable. Now you can
communicate with large main frame
computers, micro-and mini-computers and
computer networking systems (The
Source? ).
$ 95 Note: Order this package when
149 - ordering your CAI/O Board.
$24 95 for ASCII conversion program only
Additional Peripherals
Memopak® 64K memory expansion
5159
Programs:
$1 95 Home $
Finance
95 Math
Tutorial
$995 Stocks
pa Bio Rhythms
Why buy from CAI?
All CAI peripherals come with
complete instruction manuals, schematics
and a 30-day unconditional replacement
warranty. Each works with either the
Sinclair ZX-80, ZX-81, MicroAce and
Timex/ Sinclair 1000.
Our technicians are happy to answer
your questions before and after purchase.
$995 Ma E
"- Om Y y T E
I
CAI Instruments, Inc.
P.O. Box 2032
Midland, MI 48640
Phone: (517) 687-7343 Office Hours: 9:00 a.m. — 4:30 p.m.
Evening Hours (Technical Information) 6:00 p.m. — 8:30 p.m.
check, money order, VISA or MASTERCARD numbers.
Foreign orders must be made in U.S. currency.
E Orders accepted by phone or mail. For mail orders, send
Quantity
—
e —— | 11.
SUBO d
Shipping and Handling
496 Sales Tax (Michigan Resident Only)
TOTAL
O Literature, enclose $1.00
SHIPPING AND HANDLING CHARGES
E Within U.S. $5.00 Outside U.S. — F.O.B.
| Midland, MI
MasterCard/ Visa
Exp. Date
Name
Address
Ciy ri State
Phone No.
Jb...
8K ROM; 1K RAM
4K ROM; 1K RAM
Cry E15
4K ROM
Enter the following program.
10 FOR A=38 TO 63
20 FOR B=38 TO 63
30 FOR C=38 TO 63
s PRINT CHR$(A);CHR$(B);CHR$(
Fs
50 NEXT C
60 NEXT B
70 NEXT A
Hit RUN and NEWLINE. When the
screen is full, press NEWLINE,
CONTINUE, and NEWLINE. Repeat this
process until you have completed the
sequence. The same program can be
entered on the 8K ROM, and you might
want to add the line: 45 SCROLL. Our
thanks to:
A. Dan Klyver
29 Old Stagecoach Rd.
Weston, CT 06883
8K ROM
Enter the following program. For the
graphics, use the graphic on the key
indicated the number of times in ():
10 E (1), 7 (10), R (1).
20 5 (1), 10 spaces, 8 (1).
30 W (1), 6 (10), Q (1).
50 10 spaces, A$, 10 spaces.
10 PRINT AT 92,10; "Pr
20 PRINT AT 10,10;"'l
39 PRINT RT 11,10; anm
‘40 INPUT R$ :
59 LET A$=” "U-H$T'
50 LET B=LEN (A$? -186
7@ FOR X=1 TO 5
sn A 18,11;A$1x TO x+22
90 NE
1089 GOTO 78
Be sure that you are in SLOW mode,
hit RUN and ENTER. After the display
appears, type in your name and press
ENTER. Observe the results. Our thanks
to:
Mark Kluth
143 Humphrey Circle
Shawano, WI 54166
Enter the following program very care-
fully. Any underlined letters indicate that
you should use the graphics on that key.
The underlined tokens and keywords
should be entered directly from the key-
board and not spelled out. If a given
keyboard entry will not enter, hit THEN,
the keyword, backspace and delete
THEN, go forward again and continue
typing in the program.
10 REM <>E£RND1£#<>DT3<>Q#0<>
FAST VAL 11#LN P?AT <> LPRINT <>
Qff«»7( CONT | T3<>Q#0<> FAST VAL
11/LN P?AT <> LPRINT <Q FO | E
ONT /ASN -
20 PRINT-AT-11,31;: 4!
30 LET S=USR 16514
After entry is complete, SAVE on
cassette. Then be sure that you are in
FAST mode, press RUN and ENTER and
watch what happens. Our thanks to:
Scott Laska
2205 Calumet Dr.
New Holstein, WI 53061 a"
lation. $7.95
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SYNC Magazine
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THE 64K RAM PACK
e Fully built, tested and guaranteed. The use of this memory is as follows:-
O No additional power supply required. 0— 8K Sinclair ROM
O Black plastic case no larger than 16K 8 — 16K RAM that is unaffected by
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O Fully compatible with printer etc.
50 16K RAM PACK at only $49.95 (£29.95)
ALP BLE including FREE ALIEN ATTACK (7K -M/code) — value $11.00 (£5.75)
pu As reviewed in "Your Computer' — (March 1982) the leading
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No frills - just a reliable and economical way to expand your ZX81.
AS odio in ‘ZX Computing’ August/Sept 1982, the new U.K.
ZX computer publication. Available ONLY from JRS.
PLEASE NOTE: All prices are fully inclusive and are applicable for export, including airmail postage. Payment may be made in sterling
(Money Order available at your bank) or your own U.S. $ cheque, made payable to JRS SOFTWARE.
Despatch normally 7 days from receipt of order
19 WAYSIDE AVENUE, WORTHING. SUSSEX. BN13 3JU Telephone: (0903) 65691
8K ROM
1K RAM
Just For Fun
Generally SYNC prefers articles in some
depth to help you get more out of your
computer. However, we: receive many
short programs that illustrate a point,
demonstrate a technique, or show some-
thing the reader has found interesting.
“Just for Fun” shares these programs with
you. If you learn something, great. If you
have some fun, great. If you have some
that you want to share, send them to: Just
for Fun, SYNC, 39 E. Hanover Ave.,
Morris Plains, NJ 07950.
Zap
M. Hampson
You are a laser zapper on a space
cruiser on routine patrol when suddenly
your ship is under attack. Each of the
attackers is assigned a number, and each
zapper is assigned a target. A target
number appears on your screen, and you
must destroy that target and only that
one. Your performance as a zapper is
measured by the score you achieve. Each
assigned target hit is worth one point.
Your rating as a zapper is the score you
achieve. The higher the score, the higher
your rating will be. If you shoot at a
target you have not been assigned, you
get no points. Furthermore, you will have
wasted a shot and the next assigned target
appears.
M. Hampson, 7 Hereford Dr., Clitheroe, Lancs
BB7 1JP, U.K. Reprinted from The Ultimate
Magazine with permission.
Neil Dewhurst, 2 Chesterbrook, Ribchester, Nr.
Preston, PR3 3XT, U.K. Reprinted from The
Ultimate Magazine with permission.
20
You control your laser movement with
the 5 key for left and the 8 key for right.
Press 0 to fire.
Enter the program, put the computer
in SLOW mode, and hit RUN and
ENTER.
30 LET S=UAL "à"
.. "i: TAB p-p."
„P-P; “SCORE
(RND £11) F2+1
iv2 UNPLOT G.INT (RNDz20) +3
143 PRINT CHRE N
104 PRINT AT &. ar CHORE N
i 25
120 LET P=P+tINKEY &-"o"
: LOT F.i
148 IF INKÉY $ <o Bn THEN GOTO 15
IF P=6+1 OR P=24+2 THEN LET
A
158 FOR co TO 24
3 —- (INKEY
154 UNPLOT P.Z
155 NEXT =
156 PRINT AT 7.8:S
150 NEXT M
Blaster
M. Hampson
In Blaster the screen displays a field
showing a wall of 7 courses of equals
signs. Your blaster, which is on con-
tinuous fire, is indicated by an asterisk.
You have 200 shots to clear away the
wall. The movement of your blaster is
automatically to the right; to move it to
the left you must press the 1 key. The
score, showing the total number of hits, is
displayed at the end.
Type in the program without using your
RAM pack. Put the computer in SLOW
mode, hit RUN and ENTER.
Graphics notes:
Line 4: Inverse equals sign (16).
Line 6: Inverse space (16); S (16).
LET N=8
LET R=Sez
FOR z-eó TO 6
PRINT AT 2.0; “BERE
NEXT
== D
Le
PRINT " s EL
LEY P-a
LET U-PEEK 1563B6225564PEEK 1
6397
10 LET BzB-i
20 IF B=@ THEN GOTO 200
30 LET P-P-1i4-tcINKEY£-"'"lsg-iüPc
153} +(P=@}
40 PORE 12024U4Pp,1251
6@ FOR Z=128>4>* TO V STEP -17
70 IF PEEK Z-148 THEN GOTO 118%
S@ POKE 2.152
Og Poe
0 y
22 :¿2Nr112 THEN
14 GOTO 3
238 PRINT “YOUR SCORE “iN
5 PAUSE Suuuu
Qo CLS
3 RUN
Catch 25, or
Playing Left Field
M. Hampson
Your catching glove (or cup or what-
ever you want to catch with) appears as a
U. The ball comes down and you must
move to catch it in your glove. You move
into catching position by using all the
arrow keys so this requires simultaneous
four finger coordination. When you catch
the ball, a shift in graphics to the asterisk
indicates a successful catch. Your score,
which is the total of successful catches, is
displayed in the top center of your screen
throughout the game.
Type in the program. Put your com-
puter in SLOW mode, hit RUN and
ENTER.
Graphics notes:
Line 120: a period.
Line 150: the letter U.
Line 200: an asterisk.
20 LET GzunL "i10"
30 LET R-
40 LET S=6-0
100 FOR Z=00 TO VAL COD
1905 LET P-INT (RANDEVAL 10" J
110 FOR L=2-2 TO VAL
120 PRINT AT L.L+P; Tür L4#2irz
L+P#ZzvZis S
130 PRINT AT Y QR. d
IB [tT = G + (ERKRÉY tcng“ -CINKEV
== d
HAET R=R+ (INREY%S="3 "3 — {i INKEY
150 PRINT AT G.R."u"
169 IF L-«Z^Z-Q AND L+4P+ZrZ=R TH
EN GOTO VAL "2006"
170 NEXT L
200 PRINT BT G,R;"x"
210 LET S=5+Z/2 ña
220 PRINT AT Z/Z.URL "11,5
230 GOTO VAL "1850"
SYNC Magazine
EZRA GROUP II
EZRA GROUP Il
The ZX81/80/TS-1000'S are making a name
with LOW prices...
WE CHALLENGE THE SOFTWARE COMPANIES
TO LOWER THEIR PRICES!
For TS-1000/ZX81/ZX80/8K ROM
1K and 16K RAM versions
Biorhythms. . AE Ru EM ce oe ey Uu ee 1.00
Graphics Billboard ee EP Se S 1.00
ENS Dae O ay 1.00
SPINNER TM. (like Rubik S) 16K . . oe ee
mmew-a-oneich (like Etc). o oe eo ee eus 1.00
Improved Pause (ZX81)........... Lo me DE 1.00
Loea IODIOSSIOD O ea ER Re E eC Aa 2.00
CHEWTER T.M. (Like Pac M- NS ee a ch 2.95
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Random MESIG SLOW da 2.00
Self Addressed Stamped Envelope
Gets YOU our Goodies Catalog
ALL ORDERS AND CATALOG REQUESTS GET FREE
Galactic Messages PROGRAM.
EZRA GROUP II
EZRA GROUP II
P.O. Box 5222 San Diego, California 92105 (714) 584-8291
Bombs Away!
Neil Dewhurst
Your high speed bomber appears at
the top of the display as the inverse
and moves from left to right. Your targets
appear at the bottom of the display as
inverse O's. Press any key to drop a bomb
at any time. Each time the plane makes a
pass over the target area, it drops down
closer to the targets. The aim of the game
is to hit all the O's before the plane gets
too low to make another pass.
Enter the program, put your computer
in SLOW mode, press RUN and ENTER.
Graphics notes:
6: inverse space (16).
10: inverse O (16); S (16).
120, 310: inverse
140, 280, 400: inverse spaces.
145: Q.
5 SRS ¿£=UBL lu TO UAL m-
7 NEXT Z
8 CLEAR
9
e
: .
A a AAA £
FOR P-URL "Q9" TO VAL "7"
FOR @=@ TO 15
PRINT HT P,0; "Hi"
IF B THEN GOTO 14e
IF INKEYS="" OR P-7 THEN GO
LEF B1
PRINT AT R,5S; "E"
LET R=R>+1i
LET S=S42
IF S>1S THEN LET 3-8
PRINT AT R,S; ‘el’
IF R=3 THEN GOStUB 400
PRINT AT P,Q; "I
NEXT Q
NEXT P
FOR @=8 TO 15
PRINT AT P,a; "EB
22S<>PEEK (PEEK 16398725
320 IF
S#PEEK cd daa THEN STOP
SEA WAR
FOR ZX81
This game is designed for one or two players. Each player has three submarines. As a certain
number of points are reached, bonus submarines will be given. When the game is going on, the
higher the score you get, the more that hostile features will appear on the screen.
The features which appear on the screen are as follows:
Submarine, Warship, U-boat and Helicopter.
Submarine
This feature is under your own control and is loaded at the left hand side of the screen. The keys
9' and ‘0’ are the firing buttons for the upward missiles and forward missiles respectively.
The submarine can be moved in four directions; it can move upwards and downwards by
pressing keys ‘7’ and '6' respectively. In order to move forward, you press key '8' and it will draw
back to its previous position when you release the button. Also, the submarine can be moved
diagonally upwards or downwards by pressing both keys ‘8’ and ‘7’ or keys '8' and '6' respective-
ly at the same time.
U-boat
This is the hostile submarine: It drifts under the sea level randomly, from right to left. Missiles are
fired as it approaches your submarine. Destroying a U-boat scores 20 points.
Warship
This is the enemy destroyer which will release bombs diagonally as it drifts on the sea surface
from right to left.
The destruction of a warship is done by either firing a vertical missile or, when the submarine is
just under sea level, by pressing keys ‘7’ and ‘0’ which release a horizontal missile. Otherwise the
missiles will just pass under the ship bottom. Each destruction of this feature scores 50 points.
Helicopter
As you reach a certain score, helicopters appear on the left hand corner of the screen: they drop
vertical bombs as they hover above the submarine. To destroy the helicopters, vertical missiles
can be fired by pressing key ‘9’. Each helicopter destroyed scores 100 points.
"New Game—ADDER—Arcade-type game.
Shoot the numbers as they pass across the screen, but watch your total.
Each game $9.95 plus $2.00 postage/handling
Distributor Inquiries Welcome
Panda
Software,
51 Elgin Street, Shelton
Stoke-on-Trent ST4 2RD
4080 PRINT HT R,35; MU
410 LET B-üa
420 RETURN
Grand Prix
Neil Dewhurst
You have just entered the 1K Grand
Prix. The black-topped track scrolls as
you drive your white "H" car toward the
finish line. You steer by the Z and M
keys. You must avoid hitting the parked
cars and running off the road. If you do
crash, the race ends and your odometer
reading appears. Each line scrolled adds
one to your reading. The aim of the race
is to drive as many miles as possible.
Enter the program, put your computer
in SLOW mode, press RUN and ENTER
Graphics notes:
Line 40: Inverse H.
Line 50: Inverse space.
Line 60: A; inverse space; A; inverse
space.
5 LET F-Unt "-12"
10 LET P-Unt "10"
20 LET Rumana "7"
30 PRINT AT 10.P;"H"
40 LET G&-"[3"
45 LET F=F+1 MS
SQ IF RND:.53 THEN LET G$-"B
55 SCROLL EC E
50 PRINT TAB R: EE i Gs:
E “¡AT 9.P;" " AND F<=D; A F
>; AT 214.6;
70 IF R>2 THEN LET R=R-2=RND
80 IF R:<10 THEN LET R=R+22RND
: 29,LET P-P-(INKEY$&-"Z") + CINKEY
100 IF PEEK (PEEK 163984256 £zPEE
K 16399) =125 OR F<M THEN GOTO 30
110 PRINT TAB 28:;F
SYNC Magazine
SOUND with ZX-81!
SOUND with ZX-81!
MAKE AMAZING SOUND EFFECTS WITH YOUR ZX-81
ae Timex
Sinclair
D
1000 PE. cad
$49.95 THE ZON X-81
* The ZON X-81 SOUND UNIT is completely self-contained and espe- -
clally designed for use with the ZX-81. It just plugs in—no dismantl-
ing or soldering.
No power pack, batteries, leads or other extras.
Manual Volume Control on panel—ample volume from built-in loud-
speaker.
otandard ZX-81—16K Rampack or printer can be plugged into ZON
X-81 Sound Unit without affecting normal ZX-81 operation.
Huge range of possible sounds for games or: Music, Helicopters,
oCi-Fi, Space Invaders, Explosions, Gun-shots, Drums, Planes,
Lasers, Organs, Bells, Tunes, Chords, etc., or whatever you devise!
8 full octaves. Uses 3-channel sound chip giving programme control
of pitch, volume of tones and noise, all with envelope control.
Easily added to existing games or programmes using a few simple
“BASIC” lines or machine code.
* No memory addresses used—1l.O. mapped.
FULL Instructions with many examples of how to obtain effects and the
programmes, supplied. Fully Guaranteed.
Payment may be made by Bank Cheque or International Money Order in
U.S. $ or £ Sterling Payable to:
P.O. Box 6
Visa-Mastercard accepted
AE sd ade Send account +
lel pers 3182 With name & address
x
*
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+
Parser Routines
This article is the third in a series
discussing the ZX81 Parser. Since the first
two articles (SYNC 2:3 and 2:4) may have
been a bit too abstract for some readers, I
hope this discussion will pull the previous
articles together.
In the first article 1 covered the basic
concepts common to all parsers, and in
the second article I described the imple-
mentation of the parser in the 8K Basic
ROM: the character fetch routines, the
CLASS tables, and the executive routine
that was responsible for controlling over-
all operations. In this article we will look
at some of the routines that are called by
the executive to perform actual oper-
ations. These operations include, but are
not limited to, PLOTting a point on the
screen, PRINTing a character on the
screen, and executing a GOTO
statement.
RUNning a Program in Basic
Before taking up the details of any
particular command, let us review the
method used by Basic to RUN a program.
In the parser's executive routine a pointer
must be passed to the line it is to execute.
This pointer is passed to the exec(utive)
in the system variable CH-ADD. A loop
(at 066Ch in the new ROM) is responsible
for keeping track of what line in the
program we are currently executing and
where it is stored in the computer's
memory.
The way the computer stores a program
in its memory is seen in Figure 1 which
represents a single program line. The first
two bytes of the line contain the line
Figure 1: A Line Representation. — — —
Text of Line
24
David B. Ornstein
number of the represented line. These
bytes are stored in MSB/LSB (Most/Least.
Significant Byte) order. This is the oppo-
site of the standard practice with a Z80.
The next two bytes hold a standard
Z80 LSB/MSB 16-bit representation of
the length of the line, including the
ENTER (NEWLINE) at the end. When
the program has more than one line, the
computer is responsible for keeping the
records that represent each line of the
program in numerical order.
With the information supplied with
each line, the computer has enough data
to effectively “walk” through the program
from one line to the next. This is accom-
plished by adding to the address of the
first byte of the text in the line, and the
length of the line, as specified in the two
length bytes. The result of this calculation
is the address of the next line in the
program. Thus, the Run-Executive, as it
will be referred to later, must perform
only simple operations such as addition
NeErcepcon= |
to RUN a program. A basic outline of the
operations performed by the Run-
Executive is as follows:
1) Load a variable (called NXTLIN)
with 16509. This is the address of the first
line of the program.
2) Set CH-ADD equal to NXTLIN.
3) Call the parser to execute the line.
4) If there are any errors currently
logged, then stop, and report them, else,
5) If the BREAK key is depressed, stop
with a D report code, else,
6) Add to NXTLIN the length of the
current line. |
7) Go back to step 2.
Figure 2 gives the code for the Run
Time Executive. Take a moment now to
study it to get a general idea of what is
transpiring. The essential facet of this
routine is that, when a command handler
is called by the parser, it can modify the
NXTLIN pointer; this is, in fact, how a
GOTO statement works. The destination
of the line number (i.e., 100 in GOTO
SYNC Magazine
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Figure 2. Listing of the Run Time Executive.
NEXT-L INE:
LD (NXTLIN), HL
EX DE,HL |
CALL TEMP-FTR : $004D
CALL LINE-RUN s $0CC1
RES 1, (FLAGS)
LD A, 11000000b
LD (X-PTR),a
CALL X-TEMP : $1443
RES 5, (FLAGX)
BIT 7, (ERR-NR)
JR Z,STOP-LINE
LD HL, (NXTLIN)
AND . (HL)
JR NZ, STOF-LINE
LD D, (HL)
INC HL
LD E, (HL)
LD (PPC) , DE
INC HL
LD E, (HL)
INC HL
LD D, (HL)
INC HL
EX DE, HL
CALL BREAK-1 : $0F 46
JR C, NEXT-L INE
100) is evaluated, the address of that line
is found, and then the calculated address
is loaded into NXTLIN.
STOP
The STOP command is, as far as the
driver code is concerned, the most ele-
mentary of all commands. The command
handler for STOP is:
STOP: RST 8
.byte $08
The RST 8 routine will, when called,
simply load into ERR-NR the byte given
after the RST 8 instruction. In this case,
the byte is a 08h. This number is the
number-of-the-error-to-cause -1. If you
review the code for the Run-Executive,
you will see that, at the end of every line,
it checks the ERR-NR byte. If the byte is
not FFh, then the Run Executive stops
and reports an error.
NEW
The NEW command is also a very
simple command. When the computer is
powered on, the BC register pair is loaded
with 7FFFh, and a jump is made to the
initialization routine. The initialization
routine then fills every byte of memory
from BC down to 4000h with a 2. It then
goes back and decrements by 1 each of
the aforementioned memory locations. As
the computer decrements each location,
it checks to be sure that the value
obtained after the decrement was a 1. If
it was not, then the computer has found
the end of available memory, and this
address plus 1 is loaded into RAMTOP.
26
LD HL, (ERR-NR)
BIT 7, HL)
JR Z, STOP-LINE
LD (HL) , $OC
STOP-L INE:
BRIT 7$, PPR=CC)
CALL Z,COPY-BUFF
LD BC,$0121
CALL LOC-ADDR : $0918
LD A, (ERR-NR)
INC A
JR Z, REPORT
CP $09
JR NZ, CONTINUE
INC BC
CONTINUE:
LD (OLDPPC) , BC
JR NZ,REFORT
DEC BC
CALL QUT-CODE : $07EB
LD 4,918
RST 10
CALL OUT-NUM : $0498
CALL CURSOR-IN ; $14AD
JF DISPLAY-6 : $04C1
The effect of the NEW code is simply
this: load BC with RAMTOP, decrement
BC, and fall through to the initialization
routine.
GOTO
As mentioned earlier, the only steps
that the GOTO command handler must
execute to accomplish its purpose are: 1)
get the destination line number, 2) find
the address of the specified line, and 3)
load this value into NXTLIN. Let us
examine each of these individually.
First, there is the matter of obtaining
the line number specified as the argument
to the GOTO. Reviewing Perceptions in
the last issue of SYNC (which you, of
course, have on the desk in front of you),
find the entry for GOTO in the Offset
Table SYNC 2:4, Listing 2). You will see
that the first type specified was a CLASS-
6 Entry and that CLASS-6 specifies an
Integral-Expression.
As the parser examines the line in
which the GOTO occurred, it called
CLASS-6 to parse out the expression.
CLASS-6 left the value of this expression
on the calculator stack. A subroutine
FIND-INT (at OEA7 in the new ROM)
will remove a value from the top of the
calculator stack and round it down to 16-
bit integer in the BC register pair. If the
number is outside of the 0.65535 range,
then the FIND-INT routine gives Report-
B.
Now we have the required argument
for the GOTO statement. Next we must,
using this number, find the address of the
Basic line that it specifies. This type of
search routine is about as common as a
parser, and the designers of the Sinclair
ROM, fearing that they might fall short of
expectations, decided to incorporate just
such a routine into the 8K ROM. The
routine, located at 09D8h, takes a line
number in the HL register pair, and
returns the line number in BC, and the
address of the requested line (or that of
the next one, if no such line exists) in HL.
Since the first two stages of the GOTO
have been accomplished, the last stage
would appear to be easy. Indeed it is. All
we need do now is to take the address
. returned by the search routine in the HL
register pair, and place it in NXTLIN.
The GOTO command handler then
returns, and the Run-Executive continues
at the new line without even the slightest
sound of discontent.
CONT
If you look at the code for the Run-
Executive very closely, you will see that,
when an error is encountered, the current
line number is loaded into a system
variable called OLDPPC. This is the line
number to which CONT continues. There
is only one detail. If we go back to the
same line at which the error occurred,
and the cause of the error was only a
STOP statement, then as soon as we
CONTinue, we will re-execute the STOP.
The code in the Run-Executive is smart
enough to detect this situation. Whenever
an error is going to be reported, the error
number is compared with 09 (STOP). If
the error number is 09, then the current
line number is incremented before it is
saved in OLDPPC.
With that little detail out of the way, I
can now tell you how CONT works: it
loads HL with OLDPPC and jumps to
step 2 of GOTO. Simplicity.
REM
Once again we find that the advantages
of having a well-written parser at our
disposal are incredible. The command
handler for REM is simply a RETurn
instruction. If you consider this for a
moment, you will see the ease with which
it works in this system. When the RET is
executed, the Run-Executive simply con-
tinues by adding the length of the line
with the REM in it to the address of said
line. The Run-Exec then continues norm-
ally at the NXTLIN.
We hope that this discussion of a few
of the concrete command handlers will
help you to understand better the way a
computer, your computer, operates.
Until next time, same relativistic time
period, same non-Euclidian universe.
SYNC Magazine
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Introduction
The Sinclair computers can be effective
learning aids if the student or teacher has
the software to set up learning situations.
A program to assist in the learning process
should meet several criteria. First, it
should be self-explanatory. Second, it
should have different modes of operation.
Third, it should be practical as a learning
tool. Fourth, it should be usable for
various kinds of content. Fifth, it should
be enjoyable to use. The List Learning
Program discussed in this article meets
these critera. Let's look at this program
John James Hollandsworth, Box 163, Montcoal,
WV 25135.
SYNC Magazine
and how you can use it to increase your
List Learning with the Sinclair
James John Hollandsworth
learning or to help others over some of
the hurdles of list learning.
Entering the Program
Type in the entire program in Listing 1.
I would strongly urge saving your work
frequently. Spending three hours at your
Sinclair and having a power interrupt can
be frustrating. After you have typed in
and saved the entire program, congratu-
late yourself for your endurance!
Next, decide on the content for the list
you want to use with the program. This
list must consist of two columns in which
the items to be memorized are paired. I
originally designed the program for the
8K ROM
16K RAM
list of the 92 natural elements and their
symbols (this list can be found in any
encyclopedia, usually under “The
Periodic Law" or in any chemistry text-
book). This is, of course, very valuable
for anyone taking chemistry, but many
other lists are possible, e.g., a list of states
and abbreviations or capitals or other
information.
Loading the Lists
When you have your two-column list
prepared, enter it by following the steps
listed below. For the sake of illustration, I
will use the list of the 92 elements, so you
will have to make the appropriate changes
for your own list.
If you put your computer in FAST
mode for entering the program, be sure
to return to SLOW mode for entering
your lists in order to avoid the screen
flicker when the program starts running
by itself later.
1) To get into the utility list loaded
program, type GOTO 1000. NEVER,
NEVER, NEVER, TYPE RUN in this
program or you will lose your list.
2) A menu of the utility program's
functions will appear. Since you wish to
load a new list, type in 1.
3) Input the title of your program which
will appear when the program begins, e.g.,
"LEARNING THE ELEMENTS SYM-
BOLS."
4) Type in the title of the first class of
items in your list. This should be the class
with the longest strings if applicable. In
the list of elements the names of the
elements are obviously longer than the
symbols so you would type in
“ELEMENT”. If your list has two classes
of items that are about the same (such as
states and their capitals), it does not
matter which is first.
5) The program now needs to know
how many characters are in the longest
word in the first class list. In the elements
list this is 12.
6) Enter the name of the second class
(*SYMBOL-") and the length of the
longest items (2).
7) Enter the number of items in your
list (92 elements).
29
8) Now a display of everything you have
typed in appears. If you have made a
mistake, type N to start over.
9) To start entering the actual list, type
Y. At the bottom of the screen a prompt
will appear, e.g., “ELEMENT”. Type in
the first element “HYDROGEN,” and it
will be displayed beside the prompt which
will then scroll up to make room for the
“SYMBOL-” prompt. Type in “H”, and
the element prompt will reappear. Con-
tinue typing in the items until you have
finished your list, If you see a mistake in
something you have typed in, just finish
the list.
10) After you finish typing in every-
thing, the program will go into a review.
The first pair of items will be displayed
(ELEMENT-SYMBOL). If the pair is
correct, hit ENTER to review the next
pair. If either is incorrect, hit the X key
and ENTER. The prompt for your first
item will appear (ELEMENT--); type the
entry in correctly. The prompt for the
second item will appear (SYMBOL-);
type in this entry correctly. The program
then moves on to the next pair until all
have been reviewed.
11) The program asks for the name
that the program will be SAVEd under.
12) At this point you will return to the
menu. If you want to review the list again
to make changes or to doublecheck, type
in 2. If you want to change the SAVE
name, type in 3. If for some reason you
want to start over, type in 1. To SAVE
the program, hook up your recorder and
position your tape where you wish to start.
Hit 4 and ENTER and immediately hit
the RECORD button. (If you used the
elements list, the program will take 3:15
minutes to SAVE.)
13) After you have SAVEd the pro-
gram, the utility program will put you
into the actual learning program. When-
ever you need to use the utility program
again, simply type BREAK during a
PAUSE and type GOTO 1000.
Now you can enjoy the fruits of your
labor, but you must read the next section.
Using the Learning Program
When you LOAD the program or get
out of the utility program by SAVEing,
the list learning part of the program
automatically starts. This prevents some-
one from being in a position to RUN it by
accident.
The title of the list appears at the top
of the screen, and a request to type in
your name appears below it. This allows
the computer to address you personally.
Though this routine may be considered a
frill, users may enjoy the feeling of a
more personal interaction with the com-
puter in a learning situation.
30
Program Modes
After typing in your name, you will see
a program mode menu appear on the
screen. This menu gives you four modes
for using the lists you have entered.
Mode 1: Reviewing the List
The first mode is akin to running your
finger down a list as you try to memorize
it. However, when the computer does the
moving, the situation is more involving
and generally more effective. The pro-
gram goes through the list in this manner:
It flashes an item from the first list, pauses
to allow the user time to remember the
corresponding item from the second list,
and then displays the second item. This
procedure is more stimulating and helpful
as a learning technique than simply dis-
playing the pair of items simultaneously.
The speed of the display depends on
the speed number you type in: 0 is the
fastest and 9 is the slowest.
After you have gone through the items
in the first list, the computer begins again
with the items in the second list. When
you have completed this list, the first list
will again appear and the process end-
lessly repeats. So whenever you want to
go back to menu, press the Q key. Some-
times you must press twice or thrice
before the program responds. Entering Q
will also exit you from modes 2 and 3.
Mode 2: Practice Drill
In the practice drill the program will
randomly select 15 items from the first
list and ask for the corresponding match.
Then it will reverse the lists and again ask
for the match. If your list has 40 items or
more, the practice drill executes a special
feature. Each time the drill is called up,
an array E$ is used as a tally. If you
answer a question correctly, the program
“makes a note of it” and will not ask that
item pair again. This tally is erased each
time the practice drill mode is entered.
Also, you will notice that, when you do
not give a correct match, the program
pauses longer after the correct answer is
displayed. The additional time to look at
the correct answer is a study feature. At
the end of thirty questions, the number of
correct answers is displayed.
Mode 3: Speed Quiz
In this mode you are given items from
the longer list and asked for the matching
item from the shorter list. You try to get
as many of the pairs as possible in sixty
seconds. This is the reason for making
the second column shorter so that more
questions can be answered in one minute.
The computer gives you one point for
each correct answer and penalizes you
one point for each incorrect answer. If
you have no idea what the answer is, hit
ENTER. Inputting a null string in this
way will move you on to the next question
without penalty. After sixty seconds the
program stops and displays your score.
Mode 4: Fond Farewell
The final mode is simply a “Fond
Farewell” to the user. Instead of STOP-
ping, the program will PAUSE about
seventeen seconds and restart at the
beginning. The purpose of this procedure
is to prevent the user from accidentally
RUNning it. This is also an ideal place to
BREAK the program if you need to LIST
it, modify it, or get into the utility pro-
gram.
Program Features
This program provides you with a base
for a custom program of your own. Not
only can you use it for any two column
list learning that you want, but also, with
over 230 lines, you can tinker, change,
and modify to your own satisfaction.
Subroutines are placed at the beginning
of the program for faster execution. Most
of the subroutines are only a line or two,
but they do save memory. Let's note the
following subroutines especially.
Subroutine 10 is used to pick a random
number and set up the screen. If a random
number is not needed (as in the review
mode), it is GOSUB 12.
Subroutine 15 is used in the review
mode to test whether the user wants to
exit. In modes 2 and 3 it is GOSUB 16.
Subroutine 20 is used in the first three
modes in the initial display.
Subroutines 25 and 30 are used in the
drill mode. The 8K ROM has an internal
timer at memory locations 16436 and
16437 which PAUSE uses. It decrements
every time a frame on the TV is displayed,
i.e., sixty times a second. To time the
speed drill, I POKEd the values to 0. The
timer then starts counting backwards,
beginning at 65536 and losing 60 a second.
After each input, the computer PEEKs
the value to see if it has passed 61936
which is the 60 second value. Notice that
PAUSE cannot be used during this time
because it also POKEs the value.
Routines such as in lines 657-659 are
found in modes 2 and 3. These routines
are needed to add spaces to a user input
because the input has to be the same
length as the answer in the array for the
two to be compared.
The Variables
To facilitate user changes, the list of
variables used in the program is as fol-
lows:
T$: The title of the program.
C$: The name of the user entered at
the beginning.
M$: The name of the first class of
items.
N$: The name of the second class of
items.
Li: The length of the longest item in
the first list.
L2: The length of the longest item in
the second list.
SYNC Magazine
151000-ZX81
OWNERS
RAR
Jun
WIN $20,000 or more
KRAKIT" is an adventure and a treasure hunt for the ZX81
and 151000 computers. The bank account and prize money
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SOLVE 12 CLUES LIKE THIS!
Where it all began. Where the torch was first lit.
Where muscles and sinews strain. Where our heros
win acclaim. Where the symbols hold the key.
KRAKIT " consists of 12 clues on a ready-to-run ZX81 or TS1000
cassette tape (16k RAM). The answer to each clue is the name of a
country, a city or town, and a number. If you are the first qualified
entrant to solve all 12 clues and declared the winner, you receive two
tickets to the city of the secret KRAKIT™ vault location. When you arrive
at that location, a check for a minimum amount of $20,000.00 (U.S.) will
be presented to you. The amount of the prize money is augmented weekly.
TS 1000- 2X81
R
5. Due to the confidential nature of
KRAKIT" we regret we are unable to
enter into any individual
correspondence. All the required
information, including how to claim the
prize, is on the computer tape.
6. The winner will be required to sign an
affidavit of compliance with these rules.
1. The first qualified entrant to be
confirmed by the judges to have
completed all the clues correctly is the
winner.
2. There will be one winner only.
3. No persons connected to
International Publishing & Software Inc.
or their families are eligible to enter
KRAKIT "
4. This offer is not valid where Ns INTERNATIONAL PUBLISHING & SOFTWARE INC.
prohibited by law. P.O. BOX 1654, BUFFALO, N.Y. 14216
vx. m m mm um E UR ER PES Se m -—————————— m
f a Mail to: a
B Ns INTERNATIONAL PUBLISHING & SOFTWARE INC. D
ü P.O. BOX 1654, BUFFALO, N.Y. 14216 3
i Please send . copies of KRAKIT " Please print: =
E at $19.95 plus $1.50 shipping. >
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other FINE
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e GAMES + GAMES + GAMES +
MARINE RESCUE: fast action underwater
TANK TRAP: destroy enemy planes 8 land
mines
GALAXY INVADERS: repel fleets of invaders
INVADERS: the classic computer game
ZX SCRAMBLE: a fast-moving space game
CROWN 8 SCEPTER: a medieval adventure
GALACTIC COMMANDO: a space war
adventure
TRACK DOWN: an adventure in the old west
BLACKJACK: as played in Vegas
SLOTS: beat the one-armed bandits
ZX CHESS |: 6 levels: black or white: save
games
ZX CHESS II: chess master: 7 levels: champion
rated
1K CHESS: 1 level: no castling or en-passant
PLANET OF FEAR: find your stolen spaceship
INCA CURSE: get gold out of the temple
SHIP OF DEATH: free your ship from an alien
cruiser
NANTIR RAIDERS: arcade game: 4 waves of
attackers
famous arcade game: chase
ghosts in a maze
1K GAMES: 11 games for unexpanded
ZX81/TS1000
SHOOT OUT: how fast are you “on the draw”
GOBBLE MAN:
FAMILY EDUCATION & HEALTH
& ENTERTAINMENT
WEIGHT CONTROL: a personalized weight
loss program*
CONSTELLATION: your computer is your
telescope*
SOLAR SYSTEM FILE: a databank on the
: solar system*
BIORHYTHMS: plot your physical, emotional,
intellectual cycles*
BOOK OF DAYS: facts, trivia, birthdays in a
datafile*
PERSONAL RECORDS
STORAGE SYSTEM: create a personal
datafile*
FLASHCARD: memory aid, learning aid, testing
device
MOVIE HANGMAN: guess the movie; beat the
Hangman
PROGRAMMING AIDS
Z-AID 1.0: a machine code programming aid
ZX BUG: for debugging, editing & running
machine codes
ZX ASSEMBLER: powerful tool for machine
code programs
TOOLKIT: add 9 commands to basic; including
renumber
ZX FORTH: ease of basic with machine code
speed*
* comes complete with a detailed guide
DEALER ENQUIRIES INVITED.
A: The user menu input; also used in
FOR-NEXT loops.
Z: The review speed.
TOT: The total number of items in the
list.
U: Score for the drill and speed
quizzes.
F1: Flag used in the utility program.
F2: Flag-1 if the list is fewer than 40
items.
D$: Generally used for user inputs.
L$: SAVE name.
P: 16437; used in POKE after PAUSE
statements.
Q: 255; used in POKE after PAUSE
statements.
A$(?,?): Array used for first list items;
dimensioned as A$(TOT,L1).
B$(?,?): Array used for second list
items; dimensioned as B$(TOT,L2).
E$(?): Array used to keep track of
correctly answered items in drill mode;
dimensioned as ES(TOT).
Final Observations
If you SAVE the program first without
any list entered, it is ready for use with
any list. Of course, after you have entered
a list, the program and your list should be
SAVEd together. You can have as many
custom programs as you need. Changes
in the program may broaden its use in
your particular situation. $ YNC would be
interested in hearing from readers con-
cerning their use of this program. a"
1 REM LIST LEHRNING BASE PROG
RAM BY JAMES JOHN HOLLANDSWORTH.
BOX 163, MONTCOAL. HU 25135--*PH
ONE 384-354-2237
3 REM REVISED 3-4-82
4 REM TQ RUN PROGRAM TYPE
SOTO 1G
o REM TO MANIPULATE LIST TYPE
GOTO lua
10 LET B-INT (RNDATQOTI1+1
12 CLS
Pa ELE AR A HIT Q FOR ME
14 RETURN
AS. ¡LEY rhe m: INKEYS
16 IF D$="8” THEN GaTa 292
ER RETURN
¿20 PRINT "IN THIS MODE, ";C5;"
21 RETURN
„29 PRINT “YOU SAID IT uns "; OF
26 RETURN
30 PRINT TAS G; "you ARE CORREC
31 RETURN
100 PRINT T$
104 PRINT AT 5.0,’
N YOUR NAME.
110 INPUT C$
115 cits
120 PRINT "HELLO, ";C$;
125 PRINT "I WILL HELP vóu vehi
N SOME ";H$;"5 AND THEIR Mar dA S
¿THE MENU OF THINGS I CAN h
"PLEASE TYPE I
S:
. REVIEWING THE LIS
PRACTICE DRILL”
SPEED QUIZ”
EXIT THE PROGRAM”
35 “PLEASE TYPE IN THE M
UMBER OF YOUR CHOICE. "“;C$;".
140 INPUT A
142 IF A<>1 AND A<>2 AND A<>3 A
ND A<>4 THEN GOTO 348
145 CELS
150 GOTO R#2eo
200 PRINT “REVIEWING THE LIST--
205 GOSUB 28
"Y WILL DISPLAY A ";N
2108 PRINT
$;” ON THE iv rut PAUSE, THEN D
ISPLAY THE ":HM$: AFTER REVIEW
ING RLL ;i0T; I “ILL SUITTCH 5E
SHOWING THE ~ MEIC TYP
A NUMBER FROM e Ta 9--@ BEING 5
UERY FAST REVIEW AND 9 THE SLOH
215 INPUT Z
IF 2<@ OR Z>2 THEN GOTO 215
220 FOR A=1 TO TOT
225 GOSuB 12 _ m:
230 PRINT AT i190,8,B$itn)." ';
235 PAUSE 28+2+18
236 POKE P.A
240 GOSUB 15
245 PRINT AS (AD
250 PRUSE 2042410
TOA
265 FOR PA-=1 FO FOF
274 Gin i2
275 PRINT AT 18.83, A$ (Al; ';
2800 PAUSE 2442318
201 PORE P.
285 GOXUB 15
290 PRINT 881A}
295 PRUSE 22+Z+148
296 PORE F.&
300 GOZStIB 15
385 NEXT FR
3210 GOTO 228 Y
¿4300 PRINT "PRACTICE DRILL---
405 GOSLUB 22 Y 3j
410 PRINT “I WILL. GIVE: YOU i15
Mh: SS IN SUCCESTON. wat TYPE I
N Fhein WS Se FHEN Ii UILL Gt
is ¿“3 AND YOU TYPE IN TH
EC IME: ^5. PRESS ENTER TO START
412 LEF tí-u
415 INPUT Z$
419 IF F2 THEN GOTO 435
320 FOR A=1 TO TOT
425 LET EZinh)-CHR$ e
A
435 FOR A=1 TO 15
440 GOSUB 18
445 IF E£i(B)-"X" THEN GOTO 448
447 PRINT AT 9,0;"TYPE IN THE “
N$;" FOR--"
450 PRINT HT 10,8:H5:B1
4609 INPUT DS
462 GOSUB 25
465 GOSUB 16
470 IF LEN Dá=L2 THEN GOTO 475
P
NM
Q
9
O
“|
e
y qa
Hl
eu
THEN GOTO 49e
b=D $+
475 IF D$-BuàiB)
Bo 0;,"NO, IT IS ";B5$
E PRINT TA
478 PAUSE 228
479 PORE P,G
430 GOTO 427 :
¿199 IF NOT Fe THEN LET ESiIiBIz''X
“ASTROLOGY”
FOR ZX-81/80/TIMEX (16K)
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ASTROLOGY COMPUTES THE POSITION OF THE PLANETS IN THE SKY FOR
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ZX81/80/TIMEX (2K)
* THE ELECTRONIC CALCULATOR
CALCULATE REACTANCE, RESONANCE, RESISTORS IN PARALLEL, AND
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POSI-LOAD TAPE WITH INSTRUCTIONS $8.00
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32
SYN
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WE SALE PLANS YOU SAVE MONEY
SYNCHRO RIZE YOUR SINCLAIR
KEYBOARD how to add a full-size keyboard
to a ZX80 or 81. Includes instructions on how
to use extra keys for Shift Lock, Automatic
Shift, Automatic Repeat and Reset.
$5.00
POWER SUPPLY how to design and build
sepes to fit your needs.
Iti-voltage.
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this inexpensive expansion. $3.
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PHONE MODEM talk to the world with
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RS 232 the most universal serial interface
Standard on many peripherals. 50
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Kerrville, Texas 78028
SYNC Magazine
1149 PRINT “IS THIS INFORMATION
492 GOSUB 26 570 GOTO Sag CORRECT -Y ~N?
493 LET U=ti+i 3500 PRINT “YOUVE TONE VERY WELL 1145 IMPUT 1%
495 PAUSE ice Luc. POPE 1159 IF Z%="N" THEN HUN 2288
496 POKE P,Y 205 PAUSE i2e 1151 IF FToTr+4e@ THEN LET Fa-1
497 NEXT A 506 PORE F.2 1169 DIM ASITOT,L1}
508 FOR A=1 FO 15 ao? PRINT 1165 DIM BRITOT,LO)
505 GOSUB 10 3510 PRINT "I HOPE You HRVE Ebh 1170 DIM ES (Tar)
S10 IF ES(H)-"X" THEN GOTO 585 “ED YOURSELFAND LEARNED SOMETHIN 1175 CLS
512 PRINT AT 9,8; “TYPE IN THE G,” 1135 INT HT 18,8; “ENTER THE 3135
;M$;" FOR--" 312 PRINT T ITEM IN THE ist CLASS/’THEN 1
515 PRINT AT 18,8;88'8) 315 PAUSE 128 ST ITEM IN 2ND CLASSTHEN 2ND ITE
520 INPUT C$ 316 POKE P,U M IN 15T CLASS, ETC.
525 GOSsuB 25 3520 PRINT “xxrex224 HAVE A NICE 1199 FOR A=1 TO TOT
527 GOSUB 16 DAY Ap. 1200 IF NOT Fi THEN GOTO 125
530 IF LEN O#=Li THEN GOTO S54S B22 PAUSE ieee 1285 SCROLL ii
S35 LET D$=D$+" " 323 POKE P.üG 12189 PRINT M£&."-—-"7;n$&iRi
54084 GOTO 5230 324 CLS 1215 SCROLL
S45 IF D$-BH$iB) THEN GOTO_S68 325 GOTO 122 1220 PRINT N£."7--".22i
558 PRINT TAB 8,;"NO. IT IS “¿R$ 99@ CLS 1225 INPUT Z$
(B); 2935 GOTO i38 1230. IF Z%-="" THEN GOTO 1290
553 PAUSE 248 996 SAVE LS 125@ SCROLL
554 POKE P,Q 397 GOTO i8e 1255 PRINT MB: "--">
555 GOTO 575 1000 PRINT "LIST LOHDER PROGRAM” 1269 INPUT ASTRA)
560 GOSUB 380 ) 1205 GOTO 1327 i265 PRINT AS tA)
¿365 IF MOT Fe THEN LET £€€iIiBlz'Xx 2408 LET Fi-Zze 2370 SCROLL
1009 PRINT “TYPE THE TITLE OF YC 1275 PRINT N$;'--';
570 PAUSE 128 UR LIST." 1230 INPUT BTA)
S71 POKE £,8 1910 INPUT T£ 1285 PRINT B5$ihH)
572 LET U=tt+2 2411 LET P=16437 1290 NEXT A
S75 NEXT A 1812 LET Fe2=a 1292 CLS
58@ CLS 1013 LET Q-22595 1295 IF Fi THEN GOTO i320
585 PRINT "YOU GOT ";t';", ";C5; 1015 CLs 1300 PRINT AT 1@,8;" UE WILL NOU
dep 1928 PRINT "TYPE THE TITLE(SINGU REVIEW EACH PAIR OFITEMS. WHEN
S86 PRINT "A VERY GOOP SCORE IN LAR) OF THE isT CLASS OF ITEMS I THEY COME ON THE SOTTOM OF TH
DEED." N YOUR LIST. THE iST CLASS SHOU E SCREEN. HIT ENTER IF THEY ARE
590 PRINT "HIT ENTER TO RETURN LD CONSIST OF THE LONGEST ITEMS CORRECT. HIT X AND THEN ENTER 1
TO. NENU.” IN LENGTH IF POSSIBLE." F THEY URONG. THEN ENTER EACH Q
592 INPUT Of id3a INPUT H F THEM AS YOU DID BEFORE.
595 Goto eae 1235 CL3 1305 LET Fi=1
500 PRINT “SPEED ourz—---" 1940 PRINT “HOU MANY CHARACTERS 31@ GOTO 1120
505 GOSUB 28 ARE IN THE LONGEST ITEM IN THE 1320 PRINT "TYPE IN THE NAME you
518 PRINT "I WILL GIVE YOU MEN i5T CLASS?” WISH TO SAVE THIS PROGRAM UN
| S"US-TYPE IN THE "; NS: "5S. AFTER 10950 INPUT Li DER."
o SEC. I WILL DISPLAY YOUR LEARE 19055 CLS 1325 INPUT L$
I WILL GIVE YOU 1 POINT FOR A 10690 PRINT “TYPE THE TITLE (SINGU 1326 PRINT “SAVE NAME--"¿1L%4
"CORRECT ANSUER TAKE 1 POINT FOR LAR) OF THE 2ND CLASS.” 1327 PRINT
AN INCORRECT ANSUER AND NOT ra 1070 INPUT N$ 1328 PRINT
ANYTHING IF YOU ONLY PRESS ENTER 1@75 PRINT “Hot MANY CHARACTERS 1330 PRINT
. PRESS ee TQ START. ARE IN THE LONGEST ITEM IN THE 1335 PRINT "i. LORD NEW LIST ”
612 LET U= SND CLASS?” 1336 PRINT “2. SEU TEU REVISE ETA
515 IMPUT m 1050 INPUT Le n t s
520 POKE P-1,2 1085 CLS 1337 PRINT "3. CHANGE SAVE NAME
525 POKE P,uu 10890 PRINT “HOU MANY ITEMS IN ER 1338 PRINT "4. SAVE PROGRAM"
aza GOSUB 12 CH CLASS OF THE LIST?" 1339 PRINT
64@ PRINT AT 1@,8,A8 1B) 1995 INPUT FOF 1340 PRINT "TYPE IN THE NUMBER O
645 INPUT Of 1100 CLS F Your CHOICE. XF YOU ENTE
647 IF PEEK iP-1)42560xPEER (UP: 1105 PRINT "TITILE-":T5 HO TO SAVE START RECORDER AS 50
61936 THEN GOTO sae i 1110 PRINT “TITLE 15T CLASS-";M% ON AS YOU PRESS ENTER.”
3550 IF 0%-"" THEN GOTO 638 1115 PRINT "LONGEST STRING 15T C 12345 INPUT A
555 GOSUB 16 ES ¿ASS-";¿LA1 1346 CLS
657 IF LEN D$-L2 THEN GOTO Soe 1120 PRINT “TITLE 2ND CLASS-";NH 1347 IF H-4 THEN GOTO 295
559 LET ps$=033" " 1125 PRINT “LONGEST STRING 2ND C 1348 IF n-i THEN RUN 1807
559 GOTO 557 ÉS LASS-";L2 1349 IF A=3 THEN GOTO 1320
560 IF D£:2B82$i8) THEN LET U=sU-3 1130 PRINT “ITEMS IN LIST-";TOT 1350 IF A=2 THEN GOTO 1308
565 IF DS=B% (181 THEM LET U=tt+2 1135 PRINT 1388 Gora 1238
CASSETTE 1 (16K) $9.95 CASSETTE 2 (16K) $9.95
SNAKEBITE Fat the snake before it eats STARTREK Use graphic photon torpedo
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your own hazards. mobile Klingons.
BATTLE Demanding game of military FUNGALOIDS Save civilization by bombing
strategy that can be played the ever-multiplying: fungus.
by 1 to 4 players. Beware - it fights back.
CASSETTE 3 (16K) $9.95 CASSETTE 4 (16K) $9.95
STARSHIP TROJAN Pit your wits against the CRAZY-CARDS Learning the rules does not
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space-craft.
PRINCESS OF KRAAL Face the monsters hiding in Use your computer to solve
the underground complex to the mysteries of the Rubik
find the treasure and save Cube.
the Princess.
1K and 2K Program Packs also available - Write for details
Check or Money Order payable to: CLEV A Computer Ware, 92 Wyckoff Street, Brooklyn, New York 11201
New York Residents only add Sales Tax. Add $1.50 for Shipping and Handling
September/October 1982 33
Teaching
with the ZX8 1
Eric Deeson
The Educational ZX80/1 Users’ Group
(EZUG) had a triple celebration in Jan-
uary. First, we were able to breathe a sigh
of relief that we had survived a year of
frenzied activity. Secondly, we welcomed
the thousandth subscriber to our
bimonthly newsletter. Thirdly, we launch-
ed our first educational ZX81 programs,
fourteen of them in fact. Now, some
months later our “membership” has pas-
sed 1500, and we have over forty validated
and popular ZX81 programs on our list.
I make these points not because I want
to plug the group, but to show that in
Britain the year-old Sinclair micro is being
taken seriously as a teaching resource.
This will remain true, for a couple of
years at least, despite the appearance of
the remarkable Spectrum. While
Spectrum and ZX81 programs are not
interchangeable, they bear such a close
relationship that rapid conversion is
straightforward.
Our group’s directory of suppliers to
the ZX market currently lists organ-
izations producing educational software
for the machine. Also MUSE, Britain’s
leading educational computing organi-
zation, has given this record-breaking new
machine a lot of support. Some support
has come from Sinclair Research as well;
in particular their educational software
awards scheme attracted a great deal of
interest.
Although actual data are very hard to
come by, there is no doubt that already
the ZX81 is by far the most popular micro
in British schools. It compares very favor-
ably with the longer-established front
runners such as the Apple, the PET, and
the Research Machines 380Z/480Z (a
stolid, fairly old British microseries), and
it is way ahead of the popular but newer
BBC machine.
The number of ZX81s in use in British
Eric Deeson, Highgate School, Balsall Heath
Road, Birmingham B12 9DS, U.K. Eric Deeson is
the organizer of EZUG. For information about
EZUG, send two international postal coupons
(for air mail) to him at the above address.
34
schools by now may exceed 10,000. This
is as many as all other micros combined.
Such success must be seen against the
background of almost universal
antagonism by the decision makers in our
educational system. “The ZX81 is only a
toy" is a common statement from
inspectors and advisers; “Forget it,” they
say. A senior inspector with a large
education authority even publicly stated
the following: "If I come across a ZX81
in any of my schools, Ill stamp on it."
British teachers tend to have a fairly low
opinion of their advisers; such attitudes
hardly help though I believe they are
symptomatic of fear more than of any-
thing else.
In a few areas, the authorities are now
considering adopting the ZX81 as the
official machine for the primary schools
(Grades 1-6). But I know of none which
provide much of the support that the
teachers need such as courses, advice,
software development, and so on.
Yet the ZX81 continues to infiltrate
the schools at a breakneck pace, and the
teachers are joining the Educational
ZX80/1 Users’ Group at a similar pace.
The reasons for this are both external
and internal. Schools and teachers are
under pressure from pupils and parents
to provide effective computing facilities
and courses. That pressure is mainly
linked to the ZX81 since it is by far the
most popular micro in British homes.
Areas of Use
How are micros coming to be used in
British education? The answer is not just
applicable to the Sinclair range, of course,
since to some extent at least the ZX81
can attempt anything other micros can
do. And the answer is not just applicable
to Britain because educational computing
in North America is as progressive, suc-
cessful, and exciting as on this side of the
Ditch.
Furthermore, the answer is not just
applicable to schools and colleges. The
ZX81 is a help with the children's aca-
demic work at home, and many university
departments have ZX81s around.
Classroom Uses
We can break the classroom uses down
into the following categories.
Computer awareness. The primay aim
is to increase familiarity with the com-
puter and its uses. Most schools in Britain
now attempt at least a few hours of this
with all pupils.
Computer studies. The ZX81 is the
apparatus used for formal computer
instruction.
Computer-assisted learning. The com-
puter joins the army of resources available
for teaching in most subjects.
Other Uses in the School
Other school uses not directly in the
classroom include:
Administration. The computer helps
the daily routines of the school as it does
in any other business.
Interfacing. Again the computer helps
as in many other fields with data capture
and process control.
Computer clubs. Many schools have
thriving clubs in out-of-class time.
Fund raising. A major educational
activity in Britain nowadays is the use of
computer games for fund raising!
Developing software and hardware. Not
a few schools find their facilities used by
pupils (and teachers) for developing soft-
ware and hardware products for sale.
SYNC Magazine
'BYTE-BACK modules
64-K MEMORY $119. MA
INSTANTINFORMATION
ch WITH
AO BYTE-BACK'S MD-1
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WIRED and TESTED $149.95
Use your phone to connect your “LITTLE” ZX81 to the
“LARGEST” computer networks in the worid. With BYTE-
BACK’s MD-1 MODEM connected all you do is dial a
phone number (usually local), press a few keys and watch
the data appear on your TV screen. (Software is included)
This MODEM can be used in either the “originate” or
“answer” mode with selectable baud rate.
You can have immediate access to:
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e 8 Independent Relays
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e 8 Independent TTL Inputs
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e By using a single POKE command
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of each of the 8 relays.
e Your ZX80/1 can read the
Status of all 8 inputs by the use of a
single PEEK command.
e A comprehensive manual is in-
cluded that has complete application
details.
e ale ws'« E A O O A COROS
allow you to drive all standard RS-232 peripherals.
Remember with: BYTE-BACK modules you are NOT limited to using only one module at a time!
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IN STOCK!
SAME DAY SHIPMENT!
BYTE-BACK'S M-64 extends the memory of your ZX81 or
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plugs directly into the back of the ZX81 and has an
expansion port to allow you to still use a printer. No extra
power supply is required. It has all standard features plus
the area from 8-16-K can be switched out in 2-K incre-
ments for memory mapped peripherals, PROMS, etc.
Same proven reliability as our M-16 with thousands in
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EXPAND YOUR 16K SYSTEM
m: m" $59.95 KIT
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If you have a Sinclair 16K
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beyond by using BYTE-BACK
M-16 MEMORY MODULES.
You can't connect two Sin-
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THOUSANDS IN USE WITH PROVEN RELIABILITY
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Allows you to connect ZX81 to all RS-232 printers & terminals.
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TRY BYTE-BACK MODULES FOR 10 DAYS WITH NO OBLIGATION
es lo. $. 6. $0 € 4. €. & 9. 5|.6 repo. ede à * 0. 9 ^ X is € whe. v p. e
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iu us $19.95 EM-«16 Blank PG Board x 1 LIE Vo e S TOLG
M AR $59 Ci Modem Kit ou ov ER Sl i A Ee ag
CROP LUN $69 O Modem Wired and Tested .................. $119.95
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O RS-232 Module Wired and Tested ............... $69.95
Bill My O Visa O MasterCard aod
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Mail To: BYTE-BACK CO. * Rt. 3, Box 147 e Brodie Rd. è Leesville, S.C. 29070
e | ^ aM-64 Wired and Tested......... sisse
c o | O M-64 Blank PC Board ...............5.
ul N~ | L-BB-1 Kitahi Manuale os eus
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x t6 e e | Shipping and Handling $4.95
e Ln
< £
m ln sr eo | ORDER PHONE (803) 532-5812
ui" - |
be 5 S~ | Exp. Date ___ Card No.
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oy City/State/Zip
E |
à |
Figure 1. Flow Chart for Simple Q/A Routine.
INPUT
Answer
“Try Again”
Figure 2. Flow Chart Adding Scoring Feature.
Computer-Assisted Learning
Probably the main educational interest
of most teachers and parents with a ZX81
is computer assisted learning (CAL).
McGraw-Hill’s new Devils DP
Dictionary (which I hope you all get a
chance to read!) has this to say:
CAI n. (Computer-Aided Instruction.)
The misguided attempt to replace each
teacher in the Bronx with 60 on-line
terminals. CAL n. (Acronym for
CALifornia or, archaic, Computer-Aided
Learning.) A superior West Coast (USA)
version of CAI in which each teacher is
replaced by 25 on-line terminals.
Some people think that in the not too
distant future teachers will be replaced
by computers. I do not agree, even though
micros are far more effective than term-
inals. Indeed I shudder at the picture of a
school in which the children spend all
their time connected to a computer, living
like chickens in a battery farm.
(Impossible future? No! A recent book
describes how a computer could check
continuously that the user's eyes are
following the screen display!)
At the moment, however, we have
hardly taken a couple of steps along the
road to such computer systems. The
36
INPUT
Answer
Subsidiary
questions
or just
“Try again”
Help
specific
to B
Help
specific
to C
Help
specific
to D
Thorough
general
HELP
Detailed
score-
specific
reinforcement
Figure 3. Flow Chart for Diagnostic Program.
ZX81, like other established micros, can
run only fairly simple teaching programs.
It will be a long time before the PLATO
approach reaches school level!
Such programs are, on the whole,
simple mechanizations of the teaching
machine material of a couple of decades
ago. In most cases they are very crude,
with each frame (unit of teaching) being
on the lines of those shown in a flowchart
such as shown in Figure 1. To program
this kind of thing is obviously fairly
straightforward (at least, as long as the
question requires a very simple
Next Q
“objective” answer). It can be elaborated
by adding a scoring feature as shown in
Figure 2.
Teaching is not like that though. Pro-
grams must therefore progress towards
mirroring classroom technique in sophis-
tication, flexibility, and explanation. Thus
correct responses require that the user be
further checked for understanding; each
incorrect response should lead to relevant
remedial assistance. The flow chart in
Figure 1 rapidly becomes unmanageable
and must be replaced with the type in
Figure 3.
SYNC Magazine
ew!
4 NEW Handbooks for
For the first time—
AVAILABLE
IN THE USA!
your Sinclair ZX-81 or
Timex-Sinclair 1000!!
CMA A RA AAA oe oe A AAA A RIOR A AAA AAA AA AAA A AAA AAA A AAA AAA AAA AA
MASTERING MACHINE CODE
ON YOUR ZX-81
by Toni Baker
Until this comprehensive, yet easy-to- understand, handbook, there
was virtually no material available about the ZX machine code.
Using this guide you'll learn the ins and outs of ZX machine code
translation. Discover the secrets of the ZX-81, and even see how to
adapt the code to the ZX-80 machine. When you understand the
language translations between BASIC and the ZX machine code,
you'll enjoy the workings of your computer to the utmost!
49 EXPLODING GAMES FOR THE ZX-81
Edited by Time Hartnell
Galactic Intruders, Breakout, Checkers, Death Maze,
Smugglers Mold, and forty-three other favorites are all here, newly
adapted especially for you and your new ZX-81 personal computer.
This fascinating gamebook gives you programming instructions for
all 49 marvelous games PLUS complete and easy-to-understand
game rules. This wonderfully exciting hardcover playbook can be
oan se Pe
MAKING THE MOST OF YOUR ZX-81
by Tim Hartnell
All new for you and your new ZX-81, this handbook focuses on the
additional features of the ZX-81. You'll have new games and use-
ful learning tricks, and you'll also see how to write programs that
really work. It will guide you through start to finish, using each
feature and function of your new ZX-81 personal home computer.
THE ZX-81 POCKETBOOK
by Trevor Toms
This handy new programming manual really gets you into ZX-81
functions. Don t just type someone else's programs. . . now you can
create your own and understand why they work. It's fun to learn all
about computing with the ZX-81 POCKET BOOK as a guide.
You'll see what your new ZX-81 can do, and what extras will make
. see how to useZX-81 BASIC in the best
. learn to avoid frustration and retyping with program and
it able to do even more. .
ways..
data file storage and retrieval techniques—and for ZX-80 owners,
you ll learn how to convert your ZX-80 to the advanced ZX-81
capabilities. And there's so much more! This road map to the ZX-
81 can be yours—it’s worth every penny!
E APT ADA o
* Üsing these books y cie mi be amazed at how fast you'll become a ZX-81 wizard. Of course, if you don't find the books helpful and inter-
esting return them within 15 days for a full refund, and owe nothing.
XX LAE MOMO OM MOM OM MO MOM MOM MOMO O MOM OE.
RESTON PUBLISHING COMPANY c/o
Mail to:
PRENTICE-HALL INC., Book Distribution Center
Route 59 at Brook Hill Drive, West Nyack, New York 10995
Please send me my 15-day trial copies of the following titles:
MASTERING MACHINE CODE ON YOUR ZX-81, by Toni Baker, (R4262-3), $18.95
49 EXPLOSIVE GAMES FOR THE ZX-81, by Tim Hartnell, (R2087-6), $16.95
MAKING THE MOST OF YOUR ZX-81, by Tim Hartnell, (R4189-8), $16.95
THE ZX-81 POCKET BOOK, by Trevor Toms, (R9525-8), $16.95
Name
Address
City State 74 1» TIE SIAE VNLT nN ee tae PIE
mm Now you can charge your orders! Just fill in the information below:
E | VISA O O MASTERCHARGE
account # expiration date
signatur
Save! If check or money order, plus your state's sales tax, accompanies your order, publisher pays all postage and handling charges. Same money back guarantee applies.
Dept. V
V-0881-Z8-(7)
Thus high expertise, both in program-
ming and in teaching, is needed to pro-
duce material with even a little effective-
ness. Like most micros, the standard 16K
ZX81 despite its efficient use of memory
cannot hold more than short programs of
this nature. In Britain more and more
teachers are turning to larger memories
now available for the ZX81 in an attempt
to overcome this problem.
Other aspects of teaching programs also
require a great deal of attention still.
Amazingly, it is common to find spelling
and grammatical errors in material
designed for use with children. This is
inexcusable. Again, there is a skill in
formatting the screen display that too few
seem to appreciate.
So it is still early to expect the ZX81 to
be actually used to teach more than a
very few small topics in any course. There
will be progress but we must wait a
number of years to see much change.
The ZX81 As a Teaching Resource
Meanwhile, viewing the ZX81 as a
teaching resource like worksheets and
projectors does at least open up other
fairly straightforward programming
opportunities. Here are the approaches
concerned.
1) Computations in geography, eco-
nomics, maths, the sciences.
2) Development and testing of models
in those subjects and for sports.
3) Retrieval of stored data in many
subject areas.
4) Representations of data in graphical
or tabular form (with or without hard
copy).
5) Educational gaming and simulations
in social, general, and science subjects.
6) Reinforcement (drill) and testing.
7) Control of laboratory and workshop
equipment, and data capture.
Program Availability
In Britain now (early summer) perhaps
a hundred adequate 16K ZX81 programs
for learning are available. These sources
are listed separately below. The vast
majority of these are in the “reinforce-
ment and testing” category, but at least a
few are found in most of the others. For
simple administrative tasks, too, some
material has appeared. Of course, each
one of those thousands of ZX81s in use in
British schools will have available a fair
number of unpublished and fairly short
routines. Produced by both teachers and
pupils, these are intended to meet restrict-
ed local objectives or to assist familiar-
ization with the micro. There will be a
huge overlap between these, but some
will eventually surface in the form of
distributed cassettes.
However, for the moment at least,
educational software is slow-moving in
Britain. Competition is becoming fierce
as more companies appear. Yet most
suppliers must be content with sales
numbering tens a week rather than the
hundreds or thousands experienced by
the top games providers. The retail dis-
tributors are chary of handling edu-
cational material, too, as the criteria for
its assessment are foreign to them.
EZUG
An Australian journalist described this
not so long ago as sounding like a soap-
powder. However, with some 1500 folk
on roll (10 outside Britain) it must be the
world's largest machine-specific educa-
tional user group. It is in fact a daughter
of Britain's major educational computing
association, MUSE, membership of which
entitles one to obtain library programs.
EZUG can, however, supply non-
members in North America direct. _
EZUG also publishes a bi-monthly
Newsletter, a directory of suppliers to the
ZX market (rather outdated now, so
available for only £1.50 or $4.00), and
special offers such as a 64K RAM built,
fully tested, guaranteed for £53.50 or
$109.50.
Details of EZUG can be obtained by
air mail by sending two international reply
coupons to me. To ensure rapid response
it would also be wise to send coupons
when approaching the other suppliers
mentioned. All are struggling despite
often excellent products.
qx _ _ ___ s de EC REIHE E E) e HOO
BART TRUEHEART, WHERE ARE YOU?
In the Space Opera series games you are Bart Trueheart, the greatest genius hero of Earth. With your companions, the Kindly Old Professor (KOP) and his
Beautiful Young Daughter (BYD) you travel the spaceways in your faithful ship, The Rover of Space.
But this idyll cannot last . . . you have enemies. The cunnin
joined forces to form THE MALTRAXIAN ALLIANCE.
Earth is depending on you to thwart their evil plans.
SO1: THE MALTRAXIANS ATTACK
You, as Bart Trueheart, must stop the fleet of the Maltraxian Alliance before it can concentrate an
You have only your faithful ship, The Rover of Space and whatever you can capture from the enemy.
Ten levels of play.
$9.50 ($12.00 in Canada)
SO2: RAID ON COLONY ALPHA
BEM's have entered the life support dome of Earth's fir
CAN YOU SAVE THE EARTH?
the invaders are not repelled, Earth's colonization programme will end.
Fighting under the dome, you must clear the colony of invaders . .
$9.50 ($12.00 in Canada)
SOA1: DETENTION STATION INTRAG
“ADVENTURE” STYLE GAMES:
g Little Green Men (LGM's) of By-Orl and the brutish Big Eye Monsters (BEM's) of Milkorf have
d attack Earth. Time is limited and so are your resources.
st interstellar colony. You, Captain Trueheart, must lead the few space marines stationed on Alpha. If
. but be careful, if the dome is pierced no one will survive.
The professor's Beautiful Young Daughter has been captured by the Maltraxians and imprisoned in the dreaded Detention Station Intrag.
You must enter this orbital prison, find BYD and free her. Then, most difficult of all, you must escape with her from the alerted station.
This is no task for the fainthearted; only you, Bart Trueheart, could even consider such a dangerous rescue.
$13.95 ($16.95 in Canada) -
SOA2: ESCAPE FROM THE DARK SYSTEM
CAN EVEN BART TRUEHEART SUCCEED?
You, Bart Trueheart, along with the Kindly Old Professor and his Beautiful Young Daughter have been marooned in a space-lifeboat in the fearsome Dark
System.
Your only hope is to boldly land where no man has landed before . . . on Nekros, a LGM colony planet and to steal one of their starships.
You must evade surveillance satellites, police, security and military f
else can you do?
$13.95 ($16.95 in Canada)
All games are for ZX81 16KRAM
All games include instructions and designer's notes.
All orders from outside Canada include payment in American funds.
Add 10% for postage and handling.
Ontario residents add 7% P.S.T.
Send cheque or money order to:
38
TURNER, ELCY & COM.,
1285 Dundas St., (Upr),
London, Ont., CANADA.
N5W 3B3
orces while finding a ship to take you home. There is little chance of success but what
SYNC Magazine |
WANT TO BUILD A MEMORY? ADD AN I/O PORT? WE HAVE YOUR PARTS
We carry the parts you need to expand your computer; starting with a full line of Z80 support chips. If you
dle OK , and
m
need tools, we handle OK, WELL XCELITE. We stock resistors, capacitors, switches, sockets, fans,
descrete solid state devices, IC’s, including TTL, CMOS, and linear connectors,PAGE prototypin supplies,
and HAMMOND and PAC-TEC casen 19 ut it pi in. li ou see what you want give us a call, if you don't
write for our free catalog.
KEYBOARDS and CASES
KEYBOARD has 62 keys, each with
GOLD CONTACTS. Keys are mounted
to a black metal plate. On all orders we
include plans on how to convert the LIGHT BLUE BASE
extra keys for Automatic Shift, Reset, SAND COLORED PANEL
and Automatic Repeat.
TEXTURED BAKED-ON FINISH
REAR
KEYBOARD KIT 34.95 VENTILATED ON BOTTOM AND
CASE AND PANEL ARE HEAVY (.081") ALUMINUM
WIRED and TESTED 49.95
SUPPLIED WITH HARDWARE AND RUBBER FEET
PROTOTYPE BOARDS
Holes on '.100" grid |
to accommodate @
all DIP packages
EDGE CONNECTORS
WP25 120V 25W 17.03
WP40 120V 40W 20.93
PENCIL THIN IRON (NOT SHOWN)
Y 0 0 ! 4 :
HOBBY WRAP TOOL
AUTO-INDEX
DO pin connector m
40 pin connector E EAE
same spacing as Sinclair
No etched circuitry except contact fingers
allows maximum flexibility P500-1 15.95
WIRE WRAP ECW-46
PCB MOUNT ECP-46
SOLDER TAIL ECS-46
Your Choice 4.95
INTEGRATED CIRCUITS
ANTI-OVERWRAP
Horizontal power and ground busses. Two
holes on wiring side allow tack soldering
of sockets to board. P500-3 22.95
MODIFIED WRAP
TOOL WITH BIT
BW2630B........ 27.95
JOYSTICK CONNECTORS
These connectors mate with Atari joysticks
PLASTIC SHELL
PCB MOUNT
Š VACUUM BASED
. LIGHT DUTY VISE
1-1/2" WIDE JAWS
1-1/4" TRAVEL
CP.U. & SUPPORT
Z80A CPU 9.45 DATA
Z80A PIO 7.65
Z80A CTC 7.65 METAL SHELL with SOLDER CUPS sa
Z80A DMA 19.95 Straight 10 Se
Z80A S10/2 21.95 DEP-9P 1.95 DEM-9P 2.50 Made tor Datapoint
: DEM-9S 2.95 by Maxell
MEMORY Right Angle 90 cm. roule
DEP-9PRA 2.25 HOOD WITH STRAIN RELIEF 1.50
5 screw high strength shell
ALTEX ELECTRONICS
618 W. Sunset
San Antonio, Texas
78216
6116—3 . 150ns 2Kx8 10.95
CMOS Static RAM 8/77.50
Check, money order, VISA, or
Mastercharge. Add $3.00 for
shipping and handling. Texas
residents add 5% state sales tax.
Foreign orders add $10.00 for
shipping; U.S, funds only. .
Limited quanities on some items
4116-4 250ns 16Kx1 2.15
Dynamic RAM 8/14.95
2516 450ns 2Kx8 6.95
+5volt EPROM 8/48.55
1—512—828—0503
Educational Software Suppliers
The following list gives some idea of
educational software suppliers. In British
terminology “primary” education is grades
1-5; “secondary” education is grades 6-12.
“O Level” is a national examination for
10th graders.
Abies Informatics, 10 Barley Mow
Passage, London W4. Expected to launch
“Mickie,” a CAL authoring program/
language on cassette; derived from NPL's
well-known medical diagnostic program.
16K + ; £15 (?).
AVC Software, PO Box 415, Birming-
ham B17 OHD. Primary/secondary/
FE: physics, chemistry, math, English,
geography, history, French (including
Hangperson and Countdown series): £3
each. War Game (nuclear facts; inter-
active): £5. All 16K.
Calpac, 108 Hermitage Woods
Crescent, St. Johns, Working, Surrey. OL
chemistry programs; objective tests. 16K
£4.95. Some good stuff here.
Computer Training Consultants, 4
Templar Way, Rothley, Leicester. Sophis-
ticated software/manual/audio +video
commentary packages planned in physics
and computing (HE). As yet need much
polish.
Customized Electronics, 155 Marton
Rd., Middlesbrough, Cleveland. 1K junior
maths. Not seen.
Edson Electronics, PO Box 151211,
Tampa, FL 33684, USA. The only over-
seas ZX education specialist we have
come across. Not seen.
Ed ZX, 16 Grasmere Rd., Dronfield,
Woodhouse, Sheffield, 18. Excellent pri-
mary maths/English software; NUM-
PRAC (£3.45) was one of the first pro-
grams in the ZX MUSE Library and it is
still one of the best.
EZUG, c/o Highgate School, Birming-
ham 12. Well, you know about EZUG by
now.
KMC Programs, 97 Catharine St.,
Cambridge. Primary maths material from
a “user-friendly concern of retired
teachers.”
LCL, 26 Avondale Ave., Staines,
Middx. Has undertaken a major project
transferring a package of Apple 10th
grade maths programs (50 of them) to
ZX. £5 for each cassette of four pro-
grams. Not seen yet.
Parsons, 23 Coxhill Gardens, River,
Dover, Kent. Primary/secondary: art,
geography, English, French. 16K; £4.95
per cassette of several programs.
Programs in Education, 49 Brittains
Lane, Sevenoaks, Kent. Primary/second-
ary: geography, English, French. 16K.
Rose Cassettes, 148 Widney Lane,
Solihull, West Midlands. The longest
established company; primary/secondary
maths, English, French. 16K. £4.50 per
cassette of several programs.
Scisoft, 5 Minster Gardens, Newthorpe,
Eastwood, Notts. Primary/secondary:
maths/science; some with revision man-
uals. From £4.50. Good ideas, but gen-
eral polish needed.
Simon Software, Freepost, New End,
Redditch. 1/16K maths. £4 each. Not
seen.
Sinclair Research, Freepost 7,
Cambridge CB2 1YY. Have started (and
about time, too) a new software push;
including ICLs “teaching” programs. We
still have not seen these; have you?
Spencer, S. The Sycamores, Queen’s
Road, Hodthorpe, Notts. The well-known
Hodthorpe Collection; programs for
teacher development plus manual.
Turner, 3 Hillgarth, Underbarrow,
Kendal, Cumbria. Primary maths. 16K.
£4.50 each.
Video Software, Stone Lane, Kinver,
Stourbridge, West Midlands. Programs in
finance, business, etc, mainly. Most are
£5.95 and well documented. While their
programs are not specifically for educat-
ion, we recommend a number as being
suitable.
William Ellis School, Highgate Rd.,
London NW5. Geography, physics,
French; “O” Level. 16K. From £3.50. My
The Hardware:
5'"x5" P.C.Board plugs into
FIZ - FLOPPY DISK INTERFACE FOR ZX81
The Firmware: Price:
Built-in routines to save and FIZ Board $149.95 / £79.95
load programs as named files,
to create random access files
of specified length and write
& read 128 byte records, to
initialise new disks, to kill
unwanted files and to display
directory and length inform-
-ation. Routines can be used
from keyboard or in programs,
e.g. a nuber of 'load & run'
programs may automatically
run in sequence. Routines are
actioned by name in USR calls
LET E=USR WRITE,etc. E is an
error code returned to BASIC.
A simple command loads all
the routine names from ROM.
Apart from an overhead of 240
bytes the ZX81 is unaffected.
most motherboard systems
or, with our double con-
-nector , into the back of
your ZX81. There is an
on-board connector for
your 16K RAM pack/printer,
and a 34-way ribbon cable
and connector for your 35
or 40 track Shugart SA400
compatible 5%" disk drive.
The board is powered by
the ZX81 supply. The FIZ
board has a 4K ROM and 2K
workspace RAM, it occupies
memory between 8K & 16K.
An 8K program loads from
disk in approx. 11 seconds.
SEND FOR A LIST OF OUR
ZX81 AND SPECTRUM SOFTWARE.
40
Double Connector
Please state for use with 35 or
40 track dive.
suitable drive, boxed with PSU,
please write for details.
Post and packing is included in
the price, allow 28 days delivery.
Send check, or Mastercard/Visa
authorised in pounds sterling,
MACRONICS SYSTEMS LIMITED
26, SPIERS CLOSE, KNOWLE,
SOLIHULL, WEST MIDLANDS,
B93 9ES, ENGLAND.
$11.95 £5.98
We can supply a
SYNC Magazine
AARDVARK — THE ADVENTURE PLACE
ADVENTURES FOR OSI, TRS-80, TRS-80 COLOR, SINCLAIR, PET, VIC-20
ADVENTURES — Adventures are a unique
form of computer game. They let you spend
30 to 70 hours exploring and conquering a
world you have never seen before. There is
little or no luck in Adventuring. The rewards
are for creative thinking, courage, and wise
gambling — not fast reflexes.
In Adventuring, the computer speaks and
listens to plain English. No prior knowledge
of computers, special controls, or games is re-
quired so everyone enjoys them —even people
who do not like computers.
Except for Quest, itself unique among Ad-
venture games, Adventures are non-graphic.
Adventures are more like a novel than a comic
book or arcade game. It is like reading a par-
ticular exciting book where you are the main
character.
All of the Adventures in this ad are in Basic.
They are full featured, fully plotted adventures
that will take a minimum of thirty hours (in
several sittings) to play.
Adventuring requires 16k on Sinclair, TRS-
80, and TRS-80 Color. They require 8k on OSI
an on VIC-20. Sinclair requires extended
TREK ADVENTURE by. Bob Retelle — This
one takes place aboard a familiar starship and
is a must for trekkies. The problem is a famil-
iar one — The ship is in a “decaying orbit”
(the Captain never could learn to park!) and
the engines are out (You would think that in
all those years, they would have learned to
build some that didn't die once a week). Y our
options are to start the engine, save the ship,
get off the ship, or die. Good Luck.
Authors note to players — | wrote this one
with a concordance in hand. It is very accurate
— and a lot of fun. It was nice to wander
around the ship instead of watching it on T.V.
CIRCLE WORLD by Bob Anderson — The
Alien culture has built a huge world in the
shape of a ring circling their sun. They left
behind some strange creatures and a lot of ad-
vanced technology. Unfortunately, the world
is headed for destruction and it is your job to
save it before it plunges into the sun!
Editors note to players — In keeping with
the large scale of Circle World, the author
wrote a very large adventure. It has a lot of
rooms anda lot of objects in them. It is a very
convoluted, very complex adventure. One of
our largest. Not available on OSI.
HAUNTED HOUSE by Bob Anderson — This
one is for the kids. The house has ghosts, gob-
lins, vampires and treasures — and problems
designed for the 8 to 13 year old. This is a
real adventure and does require some thinking
and problem solving — but only for kids.
Authors note to players— This one was fun
to write. The vocabulary and characters were
designed for younger players and lots of things
happen when they give the computer com-
mands. This one teaches logical thought, map-
ping skills, and creativity while keeping their
interest.
DERELICT by Rodger Olsen and Bob Ander-
son — For Wealth and Glory, you have to ran-
sack a thousand year old space ship. You'll
have to learn to speak their language and
operate the machinery they left behind. The
hardest problem of all is to live through it.
Authors note to players — This adventure
is the new winner in the “Toughest Adventure
at Aardvark Sweepstakes”. Our most difficult
problem in writing the adventure was to keep
it logical and realistic. There are no irrational
traps and sudden senseless deaths in Derelict.
This ship was designed to be perfectly safe for
its” builders. It just happens to be deadly to
alien invaders like you.
NUCLEAR SUB by Bob Retelle — You start
at the bottom of the ocean in a wrecked Nu-
clear Sub. There is literally no way to go but
up. Save the ship, raise her, or get out of her
before she blows or start WWIII.
Editors note to players— This was actually
plotted by Rodger Olsen, Bob Retelle, and
someone you don't know — Three of the nas-
tiest minds in adventure writing. It is devious,
wicked, and kills you often. The TRS-80 Color
version has nice sound and special effects.
EARTHQUAKE by Bob Anderson and Rodger
Olsen — A second kids adventure. You are
trapped in a shopping center during an earth-
quake. There is a way out, but you need help.
To save yourself, you have to be a hero and
save others first.
Authors note to players — This one feels
good. Not only is it designed for the younger
set (see note on Haunted House), but it also
plays nicely. Instead of killing, you have to
save lives to win this one. The player must
help others first if he/she is to survive — | like
that.
Please specify system on all orders
PY RAMID by Rodger Olsen — This is one of
our toughest Adventures. Average time
through the Pyramid is 50 to 70 hours. The
old boys who built this Pyramid did not mean
for it to be ransacked by people like you.
Authors note to players — This is a very
entertaining and very tough adventure. | left
clues everywhere but came up with some in-
genous problems. This one has captivated
people so much that | get calls daily from as
far away as New Zealand and France from
bleary eyed people who are stuck in the
Pyramid and desperate for more clues.
QUEST by Bob Retelle and Rodger Olsen —
THIS IS DIFFERENT FROM ALL THE
OTHER GAMES OF ADVENTURE!!!! It is
played on a computer generated map of
Alesia. You lead a small band of adventurers
on a mission to conquer the Citadel of Moor-
lock. You have to build an army and then arm
and feed them by combat, bargaining, explora-
tion of ruins and temples, and outright ban-
ditry. The game takes 2 to 5 hours to play
and is different each time. The TRS-80 Color
version has nice visual effects and sound. Not
available on OSI. This is the most popular
game we have ever published.
MARS by Rodger Olsen — Y our ship crashed
on the Red Planet and you have to get home.
Y ou will have to explore a Martian city, repair
your ship and deal with possibly hostile aliens
to get home again.
Authors note to players — This is highly
recommended as a first adventure. It is in no
way simple —playing time normally runs from
30 to 50 hours — but it is constructed in a
more “open” manner to let you try out ad-
venturing and get used to the game before
you hit the really tough problems.
ADVENTURE WRITING/DEATHSHIP by
Rodger Olsen — This is a data sheet showing
how we do it. It is about 14 pages of detailed
instructions how to write your own adven-
tures. It contains the entire text of Deathship.
Data sheet - $3.95. NOTE: Owners of OSI,
TRS-80, TRS-80 Color, and Vic 20 computers
can also get Deathship on tape for an addi-
tional $5.00.
PRICE AND AVAILABILITY:
All adventures are $14.95 on tape except
Earthquake and Haunted House which are
$9.95. Disk versions are available on OSI and
TRS-80 Color for $2.00 additional.
ALSO FROM AAR DV ARK — This is only a partial list of what we carry. We have a lot of other games (particularly for the
TRS-80 Color and OSI), business programs, blank tapes and disks and hardware. Send $1.00 for our complete catalog.
AARDVARK - 80
(313) 669-3110
"aste
2352 S. Commerce, Walled Lake, MI 48088 m
Phone Orders Accepted 8:00 a.m. to 4:00 p.m. EST. Mon.-Fri.
TRS-80 COLOR
SINCLAIR
OSI VIC-20
8K ROM; 1K RAM
4K ROM 3 IK RAM
Think about maps for a minute. We
see them in one form or another almost
every day, but we usually do not think
about them even though there are some
highly sophisticated theories about maps.
We simply use them. We just want to
figure how to get from here to there.
On a computer, however, a map is
something we have to think about. Many
computer games — and other applications,
too—use maps to store and represent
information. In this article, we will
examine some ways of putting maps into
your ZX80 or ZX81. We will also see
how the Sinclair computers can generate
complex maps by themselves.
Starting at the Beginning
What exactly is a map? Let us define it
at this point as a representation of a group
of places and of the ways of getting from
one place to another.
One of the most familiar types is the
road map. Cities and towns marked on
the map with different types of dots; the
roads are shown as lines of various sizes
and colors. The towns are the places on
the map, and the roads connect each of
them to other towns.
One of the defining characteristics of a
map is that every place on the map must
be connected, somehow, with every other
place on the map. Maybe the connection
will not be direct. On a road map, for
example, the route from town A to town
B might lead through several other towns
along the way. But, if you literally “can’t
get there from here," the two places are
not really on the same map.
Actually, most road maps contain
plenty of other information besides
locations of towns and roads. For
example, since a road map is usually a
picture of an entire region, it also shows
such features as rivers and lakes.
In addition to those extra details, all
the distances on a road map are usually
to scale. “To scale" means that distances
on the road map are proportional to the
Harry Doakes, PO Box 10860, Chicago, IL 60610.
42
Maps and the ZX80/81
Harry Doakes
distances in the real world. Thus one inch
on the map might represent ten miles in
the real world. That may seem pretty
obvious, but not all maps are drawn to
scale. Many do not need to be.
Concentration
A map drawn to scale contains a lot of
information concentrated in a relatively
small space. We scan the map quickly
and get the information we need fast.
That is, we process the information the
map contains visually.
The very complete to-scale map is not
nearly so useful to a computer though.
To understand why, think about what
you do to figure out how far it is from
New York to Los Angeles.
1) You open up the map.
2) You find New York.
3) You find Los Angeles.
4) You measure the distance between
the two cities.
Now think about what a computer has
to go through to do the same thing:
1) It has to scan the entire map, one
small section at a time, to look for New
York.
2) It must repeat the whole process to
find Los Angeles.
3) Having figured out where the two
cities are, it has to measure the distance
between them. Generally that is the
easiest part of the task.
But before any of that happens, the
computer must be able to scan the map.
Since this generally means the map must
be stored in the memory of the computer,
lots of memory is required, much more
than is reasonable for something as simple
as figuring out how far it is between two
cities.
The simple truth is this: human beings
are good at processing visual information.
Computers are not. As a result, the best
kind of map for a human being may be
the worst sort of map for a computer.
A Computer Map
The simplest kind of computer map is
the equivalent of a map actually drawn
on a piece of paper. For example, enter
and run the program in Listing 1. Your
screen display should look something like
Figure 1.
Figure 1.
LÀ
=
2
a
ES
a
z
=
2
2
a
"e e& o c p &k ce uw
42
STANCE =4
Listing 1.
8K ROM
19 LET L=INT (RND£1090)
20 LET N=INT_(RND+*1080)
30 IF N-L THEN GOTO 20
RINT " "
P
58 FOR A=8 TO 9
PRINTS
YO FOR B=8 TO 9
S0 LET Af=". "
30 IF 10%+A+B=N THEN LET AS=“"N"
i9@ IF i@tAh+G6=b THEN LET Ag="L"
110 PRINT ASE:
NEXT B8B
138 PRINT "."
140 NEXT A
150 PRINT “
Changes for 4K ROM
10 LET L=RND (106) -12
28 LET N=RND (1007 -2
This is a randomly generated map of
New York and Los Angeles. The “N”
represents New York, and the “L” Los
Angeles.
It certainly looks like a map—a sort of
map, anyway. And it is relatively easy for
a human brain to understand. But it is not
nearly so easy for a computer to work
with. Remember that, using just the map,
a computer calculating the distance
between the two cities would have to
scan every space on the map to find each
of the cities. That is not too large a
problem on a tiny map of 100 spaces. But
for a map representing the entire United
States, featuring a significant number of
cities, it would take lots of time—and lots
of memory.
A human brain has a huge capacity for
processing and storing information, but a
computer (especially a small, personal-
size computer like the Sinclair) does not
have the luxury of all that spare memory.
For most computerized maps, drawing
out the map for the computer to work
with will not be very helpful.
A More Coordinated Version
The computer has several ways of
handling this information instead of act-
ually drawing out a map. One is to assign
coordinates to each important place on
the map. In Listing 1, for example, lines
10 and 20 assign a random position to
SYNC Magazine
ZX-STD BUS INTERFACE
Floppy Disc *ON-BOARD MEMORY
oe Vid. EXPANSION OPTION
DESEE. * MEMORY - MAPPED PORTS
Near * PROVIDES POWER TO ZX
Speech *ALLOWS OVER 6M CABLE
Modem * HI-POWER BUS BUFFERS
a * DELIVERY FROM STOCK |
Etc. Etc. i iii >
From over 50 manuf. TESTED Cee AA PO, AER he
Pe ae tel ck s bye NG ae —
OPTIONS: poc»
* CONVERT ZX EDGE CON.
TO RIBBON HEADER $30
E CO *2K RAM EXPANSION $15
A *4K RAM EXPANSION $ 25
ELTE TETTE,
BOX 18093 AUSTIN
TX 78760-8093 31408143000
(512) 385-7405
ABERSOFT
7 MAESAFALLEN, BOW ST, DYFED, SY24 5BA
ZX81 8 Spectrum
Games
Now NEW LOW prices!!!!
OMNI TEMPLATE
FOR ZX-80 and ZX-81
WHAT IS OMNI TEMPLATE?
Itisa template program for generating other programs.
While developing programs, our staff needed a collec-
tion of general utilities to avoid the burden of repeating
the same routines over and over. This gave birth to
OMNI TEMPLATE. We found it so effective that we
decided to share it with others.
WHY SHOULD YOU HAVE IT?
Itisa great training tool. It helps youto develop a habit
of writing professional-looking programs rather than
rag-tag patch works. It makes programming fun.
PASTAM ES WHATDO YOU GET?
Chess 1.4 $17.95 Y ou will receive a cassette tape of OMNI TEMPLATE
10 levels mc Program prerecorded and ready to use. Three addition-
al programs: RACING, INDEX-CARDS and FIT-
Adventure $17.95 POINTS, which were developed by OMNI TEMPLATE,
140 locations based on the original are on the tape in addition to OMNI TEMPLATE. A
complete listing of OMNI TEMPLATE and a well-
documented manual describing how to use OMNI
TEMPLATE is included.
HOW DO YOU GET OMNI TEMPLATE?
It is $9.50, if ordered before December 1, 1982. It
becomes $14.50 after that. Please add $1.00 for shipping
and handling. Send money order or check to:
Invaders
Fast mc arcade action
Mazeman $8.95
All the features of the original
arcade version m/c
Omni Technology
P.O. Box 10630
Pittsburgh, Pa 15235
PA resident please add 57 cents for PA sales tax.
Add $2.00 for postage/handling
each of the two cities. Finding the dis-
tance between the two cities would be
much easier for the computer if it could
Listing 2.
160 LET A=INT (N-183-INT (Lr-10)3
ET B=N-L-19:a
i980 LET A=INT SOR, Pati aidad
INT “N=";N, ab
200 PRINT “DISTANCES: UR
Changes for 4K ROM
10 LET LzRND(i1OGO0)-1
Lr
e
7
z
Y
bi
Z
O
fe
9
9
w^
|
he
+626
190 IF &«8 THEN MEER SR
"NIU: N. “pan P. t
249 PRINT “DISTANCE=":A
deal directly with the variables N and L.
The program in Listing 2 lets it do
exactly that. This time, there is no visual
map for the human being, but the com-
puter can give us the information we want
much faster because it is working with a
map is designed for it.
To get a human-readable version of the
map at the same time, combine the two
programs into one—none of the line
numbers will conflict — and run the result-
ing program. In one sense, what we have
done in the second program is to elimin-
ate all the “white space” from the first
map. Only the pertinent information is
left.
The Real World
In most computer games, it is assumed
that the whole universe is divided up into
squares, and that you always move from
one square to the next. This a system
lends itself well to simple maps.
If you are pretending to fight monsters
or shoot aliens, it may work fine, but the
real world is not so convenient. Consider
an airline route map, for example. You
can create a computer map that shows all
the territory between cities, but there is
not much point in that since airplanes
always fly directly from one Place to
another. All that “white space” just gets
in the way. Remember what a map is:
simply a group of interconnected places.
Suppose you want to make an airline
map containing New York and Los
Angeles. You might do it like this:
Places: Routes:
New York (NY) NY-LA: 2800 miles
Los Angeles (LA)
You might also include another
route — LA-NY: 2800 miles. In this case it
is safe to assume that the route goes in
both directions, but that is not always
true. If you were making a map 2 s
plumbing system or a circuit board,
might be important to know which jns
everything was moving. For now, though,
assume that there are no one-way routes.
44
Bigger and Better
Of course, there is no reason to limit
this map to two cities. Let's expand it as
in Figure 2. This looks like a long list of
interconnections, but actually it is rather
straightforward. In a computer, the
important information—the distances—
could be represented in a single one-
dimensional array which requires far less
memory than an accurately scaled visual
map.
Figure 2.
Places: Route: Miles
(1) New York (1) NY-LA 2800
(2) Los Angeles (2) NY-Ch 840
(3) Chicago (3) NY-Ho 1650
(4) Houston (4) NY-Bo 220
(5) Boston (5) NY-SF 3040
(6) San Francisco (6) LA-Ch 2100
(7) LA-Ho 1550
(8) LA-Bo 3050
(9) LA-SF 410
(10) Ch-Ho 1100
(11) Ch-Bo 1000
(12) Ch-SF 2410
(13) Ho-Bo 1860
(14) Ho-SF 1950
(15) Bo-SF 3170
The Traveling Salesman
Now suppose you are a salesman who
has to visit six cities, beginning in one of
them and ending in the same city you
started from. How can you find the route
that requires the least amount of traveling,
that is, the route that covers the shortest
distance? (This is a variation of the old
“traveling salesman” problem.)
We find that there are six-factorial
possible routes. (Six-factorial, or 6, means
6x5x4x3x2x1, or 720.) Some of these are
virtually identical, following the same
route but starting in a different city, or
running the route backwards. But even
after eliminating duplication, there are
still 60 different possibilities to choose
from. Which one is shortest?
You could figure out all the possible
routes, if you had lots of paper and lots
more time. However, with this map of the
six cities, it is easy for the computer to
figure out every route and then tell you
which circuit is the most efficient.
Listing 3 is a program to try all the
different routes. The 8K version requires
over 1K RAM. To use the program on
the 4K ROM, make the changes at the
end of the listing.
The first lines of the program load the
distances into the D array. Then P (the
current “shortest distance” for the whole
circuit) is set very high, and the A array is
set up as 1, 2, 3, 4, 5, 6 to indicate a route
through New York, Los Angeles, Chicago,
Listing 3.
1 REM 2800.0840. 1650.0220., 304
©. 2180.1550. 3659. 29419,1100, i999,
2410, 1880, 1850. 3178
26 DIM Dt15).
30 FOR D-1 TO 15
40 FOR je D
A} -28
su
XT A
128 GOSUB 10090
130 FOR D=1 TO 4
140 LET N=6-D
150 FOR A=N TO 5
169 IF AR(A+1)>A(AR) THEN GOTO 29
170 NEXT A
1580 NEXT D
190 STOP
200 LET diii: eed
210 FOR A=1 TO —1
229 IF ata) SANT THEN GOTO 296
230 NEXT A
24@ LET N=N+1
IF N=? THEN GOTO 120
ET
270 GOTO 210
LET R=8
pa
G
n
o
*
19309 FOR TO 5
1949 FOR #i TO G
A AND RID-«1)-B5B OR
+1} =A THEN GOTO 119
mONO e
pu
S
ul
9S
^E) O)
1969 IF A
aU T. RND
Pu
ZDO DON"
N
1129 IF R>P THEN RETURN
1130 is LM THEN CLS
ET =R
11580 FOR R=1 TO 7
1160 PRINT ACR};
NEXT A
1159 PRINT TAB 8P
1190 RETURN
Changes for 4K ROM
40 FOR A=16422 TO 16425
aa LET OB tO} =1GebD iO? +PEEK (Seb +48
3-2
1180 PRINT „P
Houston, Boston, San Francisco, and then
back to New York. The rest of the main
program simply generates a new route
each time, while the subroutine beginning
at line 1000 calculates how long each
route is.
It should only take about three minutes
for a ZX80 to come up with the shortest
route.
Trees
It should be clear by now that different
kinds of maps are useful for different
purposes. For a human being to find the
right highway, a road map works just fine.
For a computer to solve the “traveling
salesman” problem, we saw a better kind
of map.
A third type that has a very specialized
use is the “tree-structured” map. Remem-
ber what the defining characteristic of
any map is: it represents a group of
interconnected things. A tree-structured
SYNC Magazine
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AUTO-SHIFT FOR SELECTED FUNCTIONS-you select which shifted functions like:
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DA EE H ELECTRONICS
i 195 LELANI
a
SAN ANTONIO, TX 78242
50 NIFTY 1K
PROGRAMS FOR
THE ZX81
A large variety of great games, interesting activi-
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for the whole family.
Also available — 50 nifty programs for your Timex
1000. Same great programs. But upgraded for 2K
machine. The result is very user friendly with addi-
tional levels of play.
$9.95 each includes
postage/handling
Listings and cassettes available:
send sase for free catalogue.
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SAVE YOUR SOFTWARE $$
$11.95 FOR 4
If you have space problems,
PACK!! PACK will store 4500 (+) 8
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CHART YOUR BUDGET
Don't just enter your monthly in-
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Menu & INKEY driven 16K
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CRAPS — All work and no play
makes Jack a dull programmer! Fun
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Send check to: OVERBYTE - 902
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33904
Cassette(s) will be mailed within 3
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ARTIST
ARTIST is a ZX81 (16K RAM) pro-
gram that, with more than 30 com-
mands, helps create drawings/
paintings on screen. Features in-
clude: user's choice of brushes and
backgrounds; free mix of graphics
and alphanumerics; easy graphic
specification of lines, circles and
half-circles; ability to define, store
and recreate complex patterns
anywhere on the screen; ability to
Save the artwork on tape or print it.
ARTIST is very easy to learn and
use. 4-years old kids master its
basic commands in minutes. At the
same time, advanced features sup-
port the creativity of sophisticated
users, which can define their own
commands; for them, ARTIST of-
fers an extensive graphic command
language.
Cassette and instructions — $10
($12 outside U.S.).
From: KSOFT, 845 Wellner Rad,
Naperville, Ill 60540.
46
map has one additional characteristic: the
map begins with a single place (or thing),
and exactly one new connection is made
for each new place (or thing) on the map.
The best way to understand this type is
with an example. Let's start out with a
map like this:
New York
True this is not much of a map, but now
add some more cities:
New York
Chicago Los Angeles
Notice that the new cities are connect-
ed to New York, but not to each other.
Why not? Think about the definition of a
tree-structured map. It starts out with one
place—New York. Then, with each city
added to the map, exactly one new con-
nection is made. Thus there will always
be more cities than connections— exactly
one more, in fact.
Lets make the map still larger as in
Figure 3. Once again, there is just one
new connection for each new city. One
way of looking at this.is to say that each
new city connects to exactly one pre-
viously existing city.
Figure 3.
New York
Chicago Los Angeles
St.Louis Peoria LasVegas Sacramento
Shaking the Family Tree
How useful can a map like this be? Not
very, if you are looking for a road map.
Most cities are a little better connected
than that.
But consider for a moment a family
tree. It works exactly like a tree-
structured map. For example, Figure 4
Figure 4.
Art
Beth Charles
David Edna Fred George Henry
Irma Jack Kathleen
shows a visual map of a family tree
covering four generations. If we consider
this tree structure as a map with places
and routes (the places are people, and
the routes are lines of parentage), it will
look like this:
Places: Routes:
Art
Beth Art to Beth
Art to Charles
David Beth to David
Edna Beth to Edna
Fred Beth to Fred
George Charles to George
Henry Charles to Henry
Irma Edna to Irma
Jack Edna to Jack
Kathleen Henry to Kathleen
As you would expect in a family tree,
each new person is the son or daughter of
exactly one person already in the tree.
That means there will be just one new
connection for each new person; the
number of connections is one less than
the number of family members.
Counting Off
Now suppose we give everyone in our
family tree a number, beginning with zero,
and each family connection a number,
beginning with one. Since there is one
more family member than connections,
we find that the member and the connec-
tion have the same number. The result
looks like this:
Places: Routes:
(0) Art
(1) Beth (1) (0,1)
(2) Charles (2) (0,2)
(3) David (3) (1,3)
(4) Edna (4) (1,4)
(5) Fred (5) (1,5)
(6) George (6) (2,6)
(7) Henry (7) (2,7)
(8) Irma (8) (4,8)
(9) Jack (9) (4,9)
(10) Kathleen (10) (7,10)
Now something else becomes obvious:
the second element of each pair matches
the route number. Why? Because a tree
structure gets bigger by one place and
one route at a time. Each new place
connects, by a new route, to some pre-
vious place. Each new family member is
the son or daughter of exactly one pre-
vious family member.
This map is significantly different from
the one we made of the six cities. For that
map, we got all the distances into one
array, but to do it we used the program-
SYNC Magazine
ming trick found in lines 1030-1080. The
trick was necessary to fit the program
into 1K, but it is still a trick.
With a tree structure, there is no gim-
mick involved. We really can represent
the entire map in a single one-dimensional
array which is a very memory-efficient
way of making a very complex and
extensive map of a tree.
A-Maze-Ment
If a carefully constructed map of the
tree type be stored as an array, why not
stand the process on its head? We should
be able to use an array full of random
numbers as a maze.
We must keep a few things in mind.
First, the random numbers have to be
chosen within the right range. Remember,
every place on a map has to connect,
directly or indirectly, with every other
place. Second, to keep the maze from
being too easy we should scramble some
of the connections and add some extra
cross-connections to the basic tree
structure.
A program that does all of these things
and puts them together to generate a
complex random maze of almost any size
is given in Listing 4. The 8K ROM version
requires over 1K RAM. To use on the 4K
Listing 4.
8K ROM
10 PRINT “NUMBER OF ROOMS?"
e UT N
86 FOR A=N+1 TO ZEN
@ LET DtRI SINT t:RNDxN) +1
IF DtR} =<A-N THEN GOTO 90
110 IF RND».S THEN GOTO 150
LN A)
130 LET D (8) =D (A-N)
140 LET D(R-N)-
150 NEXT A
LET G=INT (RNDEN} +1
E
a
198 IF @>@ THEN GOTO 220
200 PRI "OUTSIDE--vYOU MADE IT
210 STOP
220 PRINT "IN ROOM ";9Q;" NITH "
230 GOSUB 4068
240 PRINT 2xN-L;" DOORS. UHICH
DOOR?"
259 IN
260 GOSUB 4180
278 IF L«»0 THEN GOTO
250
280 IF a THEN GOTO 318
2en
Po or A=56+N OR D(A} =ð T
430 IF t< Ze THEN NEXT A
440 RETUR
Changes for 4K ROM
60 IF A>1 THEN LET DthR)-zRNDtR-
@ LET D(A3=ARND C
i1! LET SAND (N THEN GO TO 158
G=RNDiN3
a? IF THEN GO TO a
P
10
r
430 IF U THEN NEXT
ROM, make the changes at the end of the-
listing.
The program is rather straightforward.
The first FOR/NEXT loop generates a
random tree structure. The second loop
adds interconnections between the rooms
of the maze and mixes up the doorways
so it will not be as easy to find the way
out. Line 160 starts the player in a random
room. The subroutine beginning at line
400 or 410 is used both to count the
number of doors in each room (GO SUB
400), and to find where each door leads
(GO SUB 410).
It may surprise you that a maze with
close to 100 rooms will fit into 1K RAM.
Enter the program and try it. You will
discover that finding your way through
the maze is quite tricky. That is because
the maze is genuinely complex: the rooms
are not laid out on any kind of flat surface,
but are completely random.
This type of mapped maze can be
adapted for use with any game that
involves a multitude of rooms or loca-
tions—caves, castles, dungeons, or haunt-
ed houses. However, it will probably
require more than 1K RAM. On the other
hand, this “different every time” is an
interesting and challenging game in itself.
EXPAND YOUR ZX81 HORIZONS
with these important books /courses!
The Complete Sinclair ZX81 Basic Course
This is probably one of the best courses on Basic available for
any computer. Also contains an excellent instruction
reference section.
What can | do with 1K?
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Roger Valentines book of Basic Programs.
Use the yo below and we'll rush your order by return.
The Complete
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September/October 1982
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GLADSTONE- ELECTRONICS
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ZX FORTH
Simplicity of BASIC with the
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‘A complete implementation of the FORTH language for
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'FORTH's most distinctive feature is its flexibility. The
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ZX-FORTH is supplied on cassette and is accompanied
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56-page Users Manual
8-page Editor Manual
Artic
ZX BUG
Machine Code Monitor and Disassembler
ZXBUG is a powerful tool for machine language pro-
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Artic $14.95
ZX
ASSEMBLER
This Machine Code program occupies 7K of memory
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GLADSTONE ‘ELECTRONICS
Artic
TOOLKIT
9 Powerful New Functions!
iRENUMBER. This routine renumbers a program in any
istep and from any line up to 9999
IDELETE. This command deletes a group of lines in a pro-
'gram.
MEMORY. Prints how much spare memory is available.
DUMP. Displays current values of string and numerical
,values, except arrays.
IFIND. Will find any string of up to 255 characters and list
leach line containing that string.
‘REPLACE. Replaces any string of up to 255 characters
by any other string.
‘SAVE. Transfers program in computer to below RAM-
‘TOP.
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GLADSTONE- ELECTRONICS
GLADSTONE- ELECTRONICS
Get serious about ZX81
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DATA STORAGE SYSTEM
For 16K or greater ZX81
PRICE INCLUDES:
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3. THREE DATA STORAGE
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4. STORAGE CASE
$34.95
SET UP FILE PARAMETERS
CREATE FILE
1FY ILE
SEARCH FOR FILE
STEP THROUGH FILES
NUMERICAL FILE
c LOCK
SAVE FILES ON TAPE
ONAMA ONP
ENTER YOUR CHOICE (1-8)
Data Storage System
An amazingly versatile multi-purpose filing system for
the 16K ZX81. The program is menu-driven, and number,
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then this program will give it plenty to think about!
The Complete ZX81
and TS1000 Library!
The Complete ZX81 Basic Course
Basic Course Cassettes (2) ..................... 7.50
Getting Acquainted with your ZX81.............. 8.95
ZX81 Pocket Book
Making the Most of Your ZX81
Computer for Kids, ZX81 Edition ................ 3.95
Explorers Guide to the ZX81
LADY COMPARISON A ei Uer i 8.95
49 Exploding Games for the ZX81
Not Only 30 Programs for ZX81 : 1K
Machine Language Made Simple for Sinclair ..
` | Mastering Machine Code on your ZX81
ZX81 Rom Disassembly: Part A
ZX81 Rom Disassembly: Part B
Understanding your ZX81 ROM
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ZX81 Professional Keyboard
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A full-sized professional keyboard for the ZX81 Features
47 keys and a full-sized space bar. Connects to the ZX81
with no soldering required, via a plug-in flexible connec-
tor. You can purchase the keyboard only, or the optional
metal case that holds both keyboard and ZX81. Expan-
sion devices (i.e. RAM packs, etc) connect to the ZX81
edge-connector which extends from the rear of the
cabinet.
A professional keyboard makes program entry easier
and less error-prone.
Keyboard (KB-1) ............... $85.00
Metal case for keyboard
and ZX81 (MC-1) ............... $25.00
J2K RAM ss.
with “piggy-back” feat
A sensible choice for 16K RAM owners. Jigsaw 32K RAM
‘piggy-backs’ onto your 16K RAM to give a total memory
of 48K! If you do not own a 16K RAM, you may use a 32K
RAM instead. At a later date you may add the ZX81,
TS1000, or Jigsaw 16K RAM, should you decide you re-
quire more memory.
A very useful, unique Jigsaw memory feature is the pilot
light showing if your ZX81 computer/memory is
powered.
Larger memory enables longer programs and greater
data bases, enhancing the value of your personal com-
puter. And the Jigsaw 32K is part of a fully compatible
ZX81 and TS1000 system of add-on products, Additional
exciting Jigsaw products to follow shortly!
64K RAM:
Expands the ZX81's memory capacity to its maximum.
Use instead of 16K RAM. Same features as other Jigsaw
memory products including pilot light and full com-
patibility with other upcoming Jigsaw products.
TGR RAM $49.95
Equivalent to ZX81 or TS1000 16K RAM. Fully compati-
ble in appearance and performance with other Jigsaw
products.
Call (716) 874-5510
For Visa, MC Orders
No CODs. Add shipping
" The Ultimate:
Adventure
With a 10,000 pounds sterling
(real money!)
pay-off
‘MY SON, by the time you receive this package, I will be
dead. This is my legacy to you. All my life | have worked
hard to make a living and save money for your future. As
you know | was an international courier. Contained on
this cassette are 12 clues of an international flavor,
which will furnish you with the information to gain ac-
cess to a bank account. In that bank account is a
minimum sum of 10,000 pounds sterling, which | have
accumulated on your behalf over the years. The longer
the sum remains in the account the greater the amount
will become. | could have bequeathed the money to you,
but I feel it is in your interest to solve these clues. Then I
will feel you are mature enough an adult to handle this
legacy.
God bless you always, your loving father. . .
So begins KRAKIT, the ultimate adventure and treasure
hunt on the ZX81. The bank account and the prize actual-
ly exist. Crack the puzzle and the prize is yours! Krakit
consists of 12 clues. In each clue there is a reference to
a country, a city or town and a number. When you have
solved the first clue, you will need to enter the two
words and the number to release the next clue. It is
necessary to solve all the clues to find the correct
answer. If you do you will be supplied with two airplane
tickets. When you arrive, a check for a minimum amount
of 10,000 pounds sterling will be presented to you. Fur-
thermore for every copy of Krakit sold a further dollar
will be placed in the bank account.
Here is the type of clue you will find in Krakit:
‘Where it all began. Where the torch was first lit. Where
muscles and sinews strain. Where our heros won ac-
claim.
Where the symbols hold the key. '
KRAKIT.16K RAM $19.95
RULES. 1. The first person to be confirmed by the judges.
to have completed all the clues correctly will be the win-
ner. 2. There will be one winner only. 3. No person
related to I.P.S. is eligible. 4. Offer not valid where pro-
hibited by law.
*Trademark of International Publishing 4 Software, Inc.
MAZDb5S
MEN EZE noUEMTURE GAME 3
3 + ; E
ek Merci Pen
m
ADVENTURE
$9.95
A new standard in ZX81 programming. MAZOGS
presents the best use of ZX81 graphics to date Written
in machine code, MAZOGS is fast, exciting, and
challenging!
You are confronted by a large complex maze which con-
tains a fabulous Treasure. Within the maze are the
Mazogs who will involve you in combat when you meet
them. Each game begins when you meet them. Each
game begins with a different randomly created maze.
You will not see all of the maze. As you move through
the halls, you will be startled by the quality of the
graphics animation and the speed with which the game
progresses.
Once you have mastered the first two levels of the game,
you are ready to challenge the Maniac Mobile Mazogs
who move about in a totally unpredictable manner.
To those who say the ZX81 is not a good games-player:
we suggest you try your luck with Mazogs! (16K or
greater)
GALAXY
INVADERS
$14.95
An excellent version of the classic space game. Protect
your seven lives against fleets of hostile invaders, who
swoop down and attack quickly. This version is an ex-
cellent demonstration of the capabilities of the ZX81 or
TS1000 to entertain and excite for hours.
ZX
SCRAMBLE-
$14.95
Pilot your space craft through a fast moving, complex
space maze. Watch out for missiles being fired from all
directions. You can shoot back or evade them. Written in
machine code for fast-paced excitement.
MARINE
RESCUE
$11.95
Your ZX81 becomes the command console as a diver
descends to the sunken submarine Nautilus to rescue
as many of the stranded crew as possible. Its a race
against time as your oxygen supply must be replenish-
ed. It’s also a constant battle against marauding sharks
which you can attempt to blast with your laser.
CHARGE TO:
lOvisa [] MASTERCARD
account number:
un nce
f
Expiry date
ORDER FORM
Pe a ete id mm
Please rush me:
To: Gladstone Electronics, 1585 Kenmore Ave., Buffalo N.Y. 14217
[ BR EE MM E NM E E E E EE E M M UM 1 M UM
Call or write for free TS1000 € ZX81 catalog
E
Signature :
$
B Date É
New York
| NAME Fee add elsa id H
ADDRESS ice
E SHIPPING M
§ ev: STATE: Bigs 0 TOTAL. .. |]
Now Choose
from 3 great
games!
ZX CH ESS EC
Full graphic display of chess board. Six levels of play,
two of which play within competitive time limits. You
choose black or white. Plays all legal moves including
castling and en-passant. You can save games in pro-
gress on cassette. Displays moves of game on screen,
or output yo printer, for analysis. Board can be set up in
any position, you can even change sides mid-game.
Clear entire board with one command: for end game
analysis. Written totally in machine code, ZX CHESS
(Enhanced) is a superb game for the advanced chess
player.
16K $12.95
ZX CHESS Il (CHESS MASTER)
The strongest chess game available on ZX81. ZXCHESS
I| has not ben beaten. All the features of ZX CHESS
(Enhanced), plus much more. Has a book of 32 opening
moves. Can play at 7 levels, four of which play within
competition time limits. A move is suggested by the
ZX81 if requested.
$24.95
16K.
1K ZX CHESS
A good introduction to chess for 1K ZX81/TS1000
owners. Even within this limited memory space, a full
graphic representation of the chess board is included.
Single level of play. Does not accept castling or en-
passant moves. $12.95
BLACKJACK
S2IUOH129313-- 3UO01SOE 12
S2JIU0OH12313- 30U01SGOE19
SJIUOHLO3T3- -H3UOISUE 19
Blackjack at its best. Blackjack as it played in the
casinos of Nevada. Up to five players can play against a
dealer with a fifty-two card deck. Split pairs, double
down, and even buy insurance. The deck is reshuffled
only when needed — allows for a continuous game.
Your winnings and losings are displayed after each
hand.
Adventure Games!
Galactic Commando ....................«.....
Crown & SCOPO iae lr Lue V on ufquc i n res
TAAK TAD Con Sie ag eae Se oe E
Slot Machine
SI14/08419313+,3U01S0819
SJIUJOH129313- 3UO01SUE'19
S2JILOH12313-- 3U01S0819 SJIUOHI12313-, 3UDOI1SOE 19
8K ROM; 2K RAM
4K ROM; 1K RAM
How Many Blocks?
Patrick Kelly
The Problem
Like most new computer owners, I was
testing my new equipment with some
games. My fun was interrupted, though,
when I realized that I was being watched.
As I turned, I was confronted by my five
year-old daughter, Scooter. Wearing a sad
face and eyes that reminded me of a
beagle puppy, she muttered, “How ’bout
me?” Needless to say, I was at a loss for
words because there do not seem to be
many programs available for her age
bracket. The obvious solution was to
write a program just for her.
Program Requirements
The first step was to outline the require-
ments for the program:
1) The knowledge or skill involved
should be within the child’s present ability
to avoid excessive failure.
2) The program should be fun and
game-like to hold the child’s attention.
3) The program should also be edu-
cational so that the child will learn from
it.
4) The means of positive/negative feed-
back should be within the child’s present
ability to comprehend.
5) The program will need minimal cues
for an adult to give assistance to get the
child started.
Patrick Kelly, PO Box 7162, Los Angeles, CA
90022.
50
Methods of Meeting the Requirements
The next step was to decide how to
fulfill these requirements. Printed words
were out of the question since Scooter
had not learned to read or write yet. She
was vaguely familiar with single printed
digits and was learning to count. Pictures
using the computer’s graphics capabilities
could also serve as a means of communi-
cation.
The Program Concept and Aim
The third step was to get the basic
program concept and aim. I decided ona
program to develop her abilities to count
and associate the counting process with
the single numerals. For positive feedback
I chose the “happy face,” and for the
negative feedback, the “sad face.” See
Listing 1 for the 4K ROM program and
Listing 2 for the 8K ROM.
Using the Program
Only 10 keys are involved in the child’s
interaction with the computer (1 to 9 and
NEWLINE). I had considered making a
keyboard overlay with a piece of paper
marked for the ten active keys, but that
would have been an open invitation to
lean on the unmarked surface with the
possibility of miskeying the computer.
Instead I just marked the case of the
computer with a small arrow pointing to
the NEWLINE key and emphasized that
she must touch only one key at a time.
After all, learning to use the keyboard is
a part of the learning exercise, too.
O »—
After entering the program, hit RUN
and NEWLINE. The words “HOW
MANY BLOCKS?” will appear on the
first line, and a row of from one to nine
blocks will be displayed on the next line.
The child should count the blocks and
press the key for that number and NEW-
LINE. If the answer is correct, the “happy
face” will appear on the screen. If the
answer is wrong, a “sad face” will appear.
To continue, hit NEWLINE. To stop, hit
any key and NEWLINE.
I hope that the pre-schoolers will enjoy
this program and learn something at the
same time. It is not offered as a ready-
made solution for every reader. Rather it
is hoped that other Sinclair users will be
inspired to develop programs for a hith-
erto neglected user group.
Program Notes
Lines 10-70 set up the faces.
Line 100 picks the random number for
the block display. On the 4K the
RANDOMIZE statement is not necessary
for a program on this simple level.
Lines 110 and 510 are the guides for
the adult. The child will disregard them
in short order.
Lines 120-140 control
display.
Line 200 inputs the child's answer.
Line 210 clears the screen to prevent
display overflow.
Line 220 makes sure that only a single
digit is entered as the answer. A zero or
multiple digits will cause the computer to
re-display the previous number of blocks
and request the answer again.
Line 230 decides whether the answer is
right or wrong, that is, which face to
display as feedback.
the block
SYNC Magazine
FROM COOK LABS — #1 IN CASSETTE SOFTWARE DUPLICATION
e Translate and/or edit T/S or ZX-81 the fast, easy way.
e Save 75% or more of valuable programming time.
RAM-to-RAM dialogue shuttles back and forth at machine
speed — faster than disc.
Meet the huge oncoming T/S software market by:
1) translating Level II libraries automatically;
2) writing and editing in either Level Il or
Sinclair Basic on a conventional keyboard.
The TransCoder I comprises a combination of software and hardware.
The hardware holds an 11-chip board that plugs directly into the expansion
port of a R/S Model I or Model III (32K min.). The several K bytes of machine
software reside in R/S high memory.
The excellent editing facilities of the host R/S computer directly apply to
. editing of T/S Basic programs because the T/S Basic listing will appear on the
screen of the R/S monitor.
Translation of Level II Basic program listings into T/S Basic is accom-
plished and displayed through software on command, with directly untrans-
latable statements flagged for the programmer's attention. Programs can then
be shuttled to T/S for final debugging and to check displays on the T/S screen.
Communication between the Radio Shack and the Timex/Sinclair oper-
ates in either direction and is non-destructive of the sending source. When com-
pleted, programs in T/S Basic can be filed on R/S disc or tape for safety and
convenient reference.
The complete TransCoder I package — hardware, software, manual — is
priced at only $490,* and will be available in early October. Orders will be filled
in sequence as received. Please write or phone if you need more information.
*Subject to change without notice.
COOK LABORATORIES, INC.
P.O. Box 529
Norwalk, CT 06856 (Phone 203-853-3641)
[] Send TransCoder I to address
given at right. I enclose check COMPANY.
or M.O. for $500 which includes
$10 for handling & shipping (Conn. ADDRESS
residents please add sales tax).
O Send information about COOK
software duplication services.
E A RNE ANO ee OWN RE A D
Line 300 displays a “sad face.” Note
that on the 4K ROM version the three
commas between each string make the
computer skip three fields between the
displaying of each graphic line so that
they will line up correctly in the corner of
the screen. On the 8K ROM only 2
commas are needed. This method was
chosen instead of multiple print statements.
Line 310 bypasses displaying an unwant-
ed “happy face” after the “sad face.”
Line 400 displays a “happy face.” All
the comments on Line 300 apply here.
Line 500 spaces one line downward.
Line 600 inputs the command to con-
tinue or to stop. NEWLINE alone will
cause the computer to continue.
Line 610 clears the screen for the next
group of blocks and prevents display
overflow.
Lines 620-640 have several functions.
First, they decide whether to continue or
to stop. If instructed to continue, they
then decide whether the child's previous
answer is right or wrong. If the answer is
right, a new set of blocks will be displayed.
If the answer is wrong, the previous set
will be displayed again. This will continue
until the correct answer is given. a"
Listing 1. How Many Blocks
(4K ROM).
10 LET As="ABAMBARARA"
ZO LET B+="ARFHRARHFRHA"
SO CERTI T ="A AWWHWWHA "
40 LET D$=" A#RWERHA "
SO LET ES="AHWIRRNRO"
OO LET FE="ARRFWRWHHRA"
TO Cee =" AH EWHHHA”
100 LET A=RND(9)
110 FRINT "HOW MANY BLOCKS?"
120 FOR I=1 TO A
120 PRINT "04%;
140 NEXT I
1S0 ‘FRIST
INFUT E
zi10 LL
24240 IF Bet OR B»9 IHEM.GOTU 11
o0 IF BREA THEN GOTO 400
SUO PRINICOBN.IIBB...UEIT.SBTPI.D
E a BBG 5.5 AA PA A A A Oe
510 GOTO 500
400 FRING * Ags, BS. 65 OS. Oo D
$45, B%,,,E%,,,F%,,,6%,,,2%,,,A%
WOO FRINT
DLO PRINT "HIT N/L TO DONTINUE"
600 INFUT HS
610 GUS
620 IF H$="" AND NOT B=A> THEN G
UTD 140
6530 IF H$="" THEN GOTO 100
640 STOP
Listing 2. How Many Blocks (8K ROM;
over 1K RAM). —
io LET A$="AAAARARAA"
2O LET RéE="ARRHRRARRA"
SUE DDR Có="ARDDHDDHA"
40 LET D=” A##Z61 2614 HHA
20 LET ES= "ORDIHBDIÓA"
60 LET F$z-"ABPEDRDEHHEA"
7O LET G$-"OSEHEDEERA"
100 LET A=INT (RINDA) +1
110 PRINT "HOW MANY BLOCKS?"
115 PRINT
120 FOR I=1 TO A
130 PRINT "Si";
140 NEXT 1
200 INPUT E
210 CLS
220 IF Bi OR B>9 THEN GOTO i
230 IF B=A THEN GOTO 400
ZOO FRINT A&S,,BS,,CS,,B¢,,D%,,8
$,,6%,,F%,,E%,,8¢,,A%
310 GOTO 500
400 PRINT A$,,E$,,0$,,E$,,D$,,É
£,,E%,,F%,,G6%,,B%,,A¢
BOO PRINT
310 FPFRINT.-"HIT N/L TU CONTINUE"
600 INPUT H$
610 CL3
620 IF H$-"" AND Bera THEN GOTO
110
630 IF oHt-"" THEN BOTH d00
640 STOF
the BEST yet
from M.C. Associates
PELOPONNESIAN WAR
— a brand new 16K game
Your ultimate goal is a final victory over the Spartans but
you will need to deploy all your skill in a combination of
diplomacy and military force before you even stand a
chance!
also
(16K)
(16K)
TYRANT OF ATHENS
ROMAN EMPIRE
Buy more than one cassette and deduct $1 from the
price of each.
Cheques or IMO's please — made payable to:
M.C. ASSOCIATES
4 GRANBY ROAD, CHEADLE HULME
CHESHIRE SK8 6LS
U.K
warlords?
Price $14
Price $14
Price $14
LOTHLORIEN -
COMPUTER GAMES
New release Warlord
A16K game set in 13th Century Japan
€ Can you rule a warring village to survive for 30 years?
€ Can you defeat the armies and samurai of other
e A challenging game where all results are dictated by
your own decision.
“SAMURAI WARRIOR"
Could you survive in 13th century Japan?
e |n combat with other Samurai
e Fighting bandit groups
* Assisting villages
or will you commit ritual suicide?
Become engrossed in this game of skill for only $14
Buy both for just $25
Cheques or IMO's please — made payable to:
LOTHLORIEN COMPUTER GAMES
94 Flixton Road, Urmston,
Manchester M31 34D
Price $14
(16K)
Get the most from your SINCLAIR
with these practical, program-filled books from Sync!
The ZX81 Companion teway Guide to the
by Bob Maunder Your ZX81 ZX81 and ZX80
The ZX81 Companion follows the same by Tim Hartnell by Mark Charlton
format as the very popular 2X80 This informative volume for the new The Gateway Guide is a practical pro-
Companion, and assists the ZX81 user ZX81 user contains more than 70 pro- gramming manual for the beginner that
in four applications areas: graphics, grams to help the reader get the most furnishes over 70 fully documented pro-
information retrieval, education and from his Sinclair computer. Game grams. The majority of the programs
games. This practical guide contains programs include Checkers, Alien have been written for easy conversion
scores of fully documented short rou- Imploders, Blastermind, Moon Lander, from machine to machine (ZX81, 4K
tines plus complete programs and a dis- Breakout, Star Burst and Derby Day. The ZX80 or 1K ZX80). The Gateway Guide
assembled listing of the ZX81 ROM book also shows programs for cascad- describes each function and statement,
Monitor. “Thoughtfully written, detailed, ing sine waves, plotting graphs and illustrates it with a demonstration rou-
and illustrated with meaningful pro- tables, data sorting, equation solving, tine or program, and combines it with
grams."—MUSE plus the use of PLOT, SCROLL, PRINT, previously discussed material to help
5'2" x8", 132 pages. #17P $8.95 ($2.00) TAB, PEEK, POKE and much more! you understand your computer.
5⁄2" x8",120 pages. #15Y $8.95 ($2.00) 52" x 8",172 pages. #160 $8.95 ($2.00)
Computers for Kids (Sinclair Edition) by Sally Larsen
This new edition of Computers for Kids is written specifically to introduce
children aged 8 to 13 to the ZX81. The book requires no previous knowl-
edge of algebra, variables or computers, and it enables a youngster to
program a ZX81 in less than an hour. There's also a section for parents
and teachers. “Computers for Kids is the best material available for
introducing students to their new computer.”
—Donald T. Piele, Professor of Mathematics,
li University of Wisconsin-Parkside.
a 812" X 11", 56 pages. #12S $3.95 ($1.00)
All volumes are softbound.
(C T Waa ee
Creative Computing Press, Dept.Z020, 39 East Hanover Ave., Morris Plains, NJ 07950
ü ks li . O Enclosedis$-.— 3— | . .NJresidents add 5% sales tax. i
isted below: xs
E Please send boo = O Charge my (Charge and Phone Order $10 minimum):
Item No. (P&H) | Total Price O American Express (MasterCard O Visa 1
- MEME Gard Number — Exp. Date 4
ignature
: E ac. Signat i
Mr./Mrs./ Ms. (please print full name)
Postage and handling charges appear Addres
1 d ee ier ) next to price of i
OK. : :
| outside U.S.A. add $3.00 per order— City/State/Zip É
shipped air mail only. CHARGE ORDERS—For Your Convenience PHONE
TOLL FREE 800-631-8112, In N.J. Only (201) 540-0445.
CHIRPER module for your ZX81
The CHIRPER module lets you enter keyboard
data fast and accurately. A sound can be heard
when a key has been entered enabling you to
spot a double entry or missed entry without
looking up at the screen.
The CHIRPER sound is produced when a pro-
gram runs. A key entry results in a buzz-like chirp
on 1K or 2K machines. Large programs in a RAM
pack produce a continuous sound that chances
pattern on key entry.
The CHIRPER module installs easily inside the
ZX81 case with only 3 wires to connect. Complete
installation instructions included.
To order your CHIRPER send a check or money
order. We pay the postage in the U.S.A, else-
where include first class postage forthree ounces.
AUDIOGCGRAPH CO.
3584 Leroy, Ann Arbor, MI 48103
L-———Á— M ———————————————————————————————ÁÁ
Keyboard
Audio Tone
Audio Keystroke
and Program Monitor
* TWO TONE. One to indicate initial
press of key, the second tells you when
computer is ready to accept next entry
(very useful when entering long pro-
gram listing)
“Indicates start and finish of running
programs, and start and end of SAVE
and LOAD routines
“Indicates Keyboard entry during
INPUT prompts
“Use to indicate progress of running
programs, or for sound effects in
MES programs, by including short
AUSE in listing.
* Operates in FAST and SLOW modes,
with normal or shifted keys
* Only five simple connections to ZX81
POS,
aie
|
|
Supplied ASSEMBLED complete with
fitting instructions
$18.00 ASSEMBLED. Includes post-
age/shipping.
Cheques and money orders payable
to:
TV SERVICES OF CAMBRIDGE LTD
CHESTERTON MILL
FRENCH’S ROAD
CAMBRIDGE CB4 3NP
ENGLAND.
Tel: (0223) 358366
54
8K ROM; 2K RAM
4K ROM; 1K RAM
Elimination A Dan Klyver
Elimination is a traditional dice game
which provides a worthwhile vehicle for
teaching young children (and others)
simple strategy, an understanding of odds,
and the mental manipulation of numbers.
Consequently, it helps reinforce arith-
metic skills since the player’s ability to
use mental arithmetic is pitted against the
computer’s problem posing ability.
Although the game is fun to play alone, a
group can play by each taking a turn and
keeping score to see who can do the best
job of eliminating numbers.
Enter the program in Listing 1 and hit
NEWLINE. The numbers 1 to 9 will
appear together with the randomly pro-
duced results of a dice roll. You are
prompted to make a choice(s) of which
number or numbers you wish to eliminate
in the range of 1 to 9. See Figure 1. The
total of the numbers selected for elimi-
nation must equal the total of the dice
role. For example, if on the first roll of
the game, you roll a 5 and a 4, you may
eliminate a 9 or any combination of
numbers totaling 9.
The object of the game is to eliminate
all of the numbers. The selection of a
given number or combination of numbers
is up to the player, but the odds of rolling
any particular number should be consid-
ered when making the selection.
After making the selection, hit
NEWLINE. The selected numbers will
become zero(s). This will indicate that
they have been eliminated and cannot be
played again. The results of a new dice
roll will also be displayed. The game
proceeds with the next selection.
Improper entries will result in early
termination of the game (a penalty for
making a mistake). When the game is
approaching the end, a roll that is not
compatible with the remaining numbers
will terminate the game with the total of
the remaining numbers being displayed
as the score. The lowest number wins.
To play again, hit NEWLINE. To revert
to the program listing, enter four letters
and hit NEWLINE. After a “win” is scored
(all numbers eliminated), the program will
be listed again.
A. Dan Klyver, 29 Old Stagecoach Rd., Weston,
CT 06883.
4K ROM Version
The program listing is for the 8K ROM,
but it can be adapted to the 4K ROM by
making the following changes:
1186 RANDOMISE
120 LET X=RND (63
6?
NT “ENTER YOUR AO e
TIME ERCH FOLLOUED
200 IF NOT 510)=06 THEN GOTO 278
250 IF NOT T=B51(T) THEN GOTO 272
; “GAME OVER. TO REPLAY
HIT ENTER"
450 IF NOT B(A) =6 THEN GOTO 59
— — — Listing 1. Elimination (8K ROM).
ae ERN 5 (9)
OR A=1 Tu 8
50 LET BR? =A
2 NEXT n
PRINT "THE NUMBERS TO BE EL
IMINRTED ARE”
560 PRINT
70 FOR A=1 TO 9
39 PRINT BiímR);" ';
NEXT A
30 NE
1990 PRINT
110 RAND
120 LET X-INT (RND*#6) +3
130 PRIN
148 LET Y=EINT {RND #5? +2
150 LET
Z¿=X>+
150 PRINT "YOU ROLLED A ";x;" m
PRINT 3
189 PRINT "ENTER YOUR CHOICES)
ONE AT A TIME EACH FOLLOUED 5
wv L an
190 INPUT @
208 IF 810)<>0 THEN GOTO 278
205 IF Q-z THEN GOTO 420
210 INPUT R
220 IF BiR):52R THEN GOTO 278
225 IF R+98=Z THEN GOTO 418
230 INPUT 3
240 IF S<¢>28t5)} THEN GOTO 270
245 IF GQ4R45-Z THEN GOTO «408
250 INPUT T
260 IF T<>B1tT) THEN GOTO 270
265 IF 84+R2537F=Z2 THEN GOTO 395
P
"GAME OVER, TO REPLAY
“SCORE=";U
GS
ER 9
450 IF Bn) <8 THEN GOTO Se
460 NEXT A,
479 PRINT “YOU WIN”
Figure 1. Sample Run.
THE NUMBERS TO BE ELIMINATED REE
«od aeo oco
YOU ROLLED A i AMD A 1
ENTER YOUR CHOICES! ONE RIF A
TIME EACH FOLLUOUED By Heri
SAME OVER, FO REPLAY HIT Wet
ScCoRE=a
SYNC Magazine
Arithmetic with a Smile
George J. Repicky
The computer as an instructional tool
is perhaps nowhere more successful than
in conducting arithmetic practice drills.
Unlike the typical classroom teacher, the
computer never tires and never makes a
mistake. It provides arithmetic practice
and never forgets to reward a right answer
with a smile.
Addition
Enter the program in Listing 1 and then
RUN it. This is the basic program. It will
generate an addition problem and print it
in the upper left hand corner of the
screen. The computer then awaits the
user’s answer. If the answer is correct,
the complete problem with the correct
answer is displayed, and the user is re-
warded with a smile. After a five second
pause a new problem is displayed. If the
answer is wrong, the problem is again
displayed along with the incorrect answer.
The user is again asked the question while
a frown is displayed. Entering a letter
instead of a number will stop the
program.
Listing 1. Addition Practice.
LO@ LET A=iNT tRND 228)
140 LET Y-INT (RNDExIUI
268 PRINT EL erui e fmm
208 PRINT X," + “¿Y = “¿Z
218 FOR N-i TO 28
2280 PLOT ISIN iNxP1/-/18)3201,3%
à (NAPI“ 123922
230 NEXT N
240 PLOT 26,20
250 PLOY 36,25
260 PLOT 31,22
28 PLOT 31,17
2230 PLOT 22,17
298 PLOT 32,17
308 IF FiomxeyY THEN GOTO ose
: PLOT 29,1383
328 PLOT 23,13
2368 PLOT 23,185
PRINT
aam GOTO dues
49 Roosevelt
George J. Repicky, Ave.,
Schenectady, NY 12304.
September/October 1982
Other Arithmetic Operations
The other arithmetic operations can be
done with the following modifications to
the program in Listing 1:
Subtraction
140 LET Y=INT(RND*X)
160, 200, 300: Change + to -.
Multiplication
160, 200, 300: Change + to *.
Division
130 LET Y=INT(RND*9)+1
140 LET X=INT(RND*10)*Y
160, 200, 300: Change + to /.
For those who do not need a smile or
frown to make the drill more lively, the
lines generating the face can be omitted.
Notes
Addition
110: Sets the seed of the random num-
ber generator.
130: Sets the range of numbers the
random number generator can choose
from for one number of the drill problem.
To increase the range, increase the num-
ber in parentheses. This will give more
difficult problems, but a bit more memory
may be necessary. If so, delete Lines 150
and 190.
8K ROM; 1K RAM
4K ROM; 1K RAM
140: Does the same for the other num-
ber of the problem.
160: Presents the problem.
170: Inputs the user’s answer.
200: Presents problem with user's
answer.
210-230: Draw face outline.
240-260: Draw eyes and nose.
270-290: Draw part of mouth.
300: Branches to reprint problem and
frown for wrong answer.
310-320: Complete the smile.
330: Generates 5 second pause.
340: Goes back to present next pro-
blem.
350-360: Complete the frown.
380: Returns to input the user’s next
answer.
Subtraction
140: Provides a problem with a non-
negative number.
Division
130, 140: Assure that the dividend is
evenly divisible. n"
Listing 2. Addition Practice (4K ROM). ..
110 RANDE I SE:
LOU ES
1:30 LET X=END (010) 1
14% LET Y=RNOCLO)-1
1500 PRINT
160 PRINT %s"R#+# Ya CH="
TAEA ENTE
180 CES
LYO PRINT
200 PRINT Xa "StH sg Ye Hed: Z
210 PRINT
220 PRINT
LO, FRENTE
240 PRINT
250 PRINT
269 FRINT
2C PRINT
ABO PRINT ,"EHASHHEETHSHE'"
290 PRINT ,"D'","44D"
200 PRINT , "RHE" |
210 IF NOT Z=X+Y THEN GO TO 340
SUO PRINT CHRE (L5G) 9 SWE
at: Aste a Ey p
HE ARDE ©
«EGR HE"
y REE ARE: "
QUDBRIBRHEEREHERD"
240 PRINT "EW"
350 PRINT , “HESHEHESHE"
Z360 REM
270 PRINTO, "RE", "RE"
280 PRINT , “HREFR+DERE"
390 PRINT
400 IF NOT Z=X+Y THEN GO TO 160.
410 INPUT I$
420 RUN
Ye
Subtraction
140 LET Y=RND¢X+1)-1
LSO: 200, SIO, 400s
Change the + to -
Multiplication
160; EE, 4d $ 400:
Change the + to *
Division
120 LET Y=KND(9)
140 LET X-(RNDGC1OO-10XY
£60, “2008 Vato, 4003
Change the + to /
55
2 AMP
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As you expand your system
you'll need more power to run it.
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PUT YOUR TIMEX/SINCLAIR
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TIMEX/SINCLAIR SOURCEBOOK
e SOFTWARE
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e BOOKS/CATALOGS
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Micro Design Concepts
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56
8K ROM; 2K RAM
4K ROM; 1K RAM
Arithmetic Series Quiz
Richard Van Workum
One exercise to sharpen arithmetic
skills is to use a series of numbers which
require discerning the relationships of the
numbers in order to complete the series.
The program in Listing 1 will print out an
arithmetic series. Your task is to figure
out the next two numbers in the series. If
you are not successful in two tries, the
answer is given.
Line 1 stores the data to construct each
series. Memory is saved by using the
alphabet for storing two digit numbers in
the same way that the hexadecimal system
uses A to F for representing 10 to 16 in
the decimal system. Data is stored in
Richard Van Workum, 920 Leslie Ln., Hanford,
CA 93230. Program translated to 8K ROM by
James Grosjean.
Listing 1. Arithmetic Series Quiz Program (8K
ROM).
1 AS EI
815926hz3074BBFCJZ405S6679BZ8S4
563782420042664702bs55eSbze42645
ASZO257ACFHKZ IL SNSP7RIZASO5G542 1
2705 CEZCBOSS65220700244658f!
ZzZO5162730423205427642024413535524t€0
o trees
D Ut1i2)
i5 DIM 6125
28 L R=INT (RNDx*10G0;5 +1
22 LET K=8
25 LET Lzà
32 . M=1651I3+INT (RNB#2i97}3 +1
2 IF "n "Rr THEN SOTO 50
+1
S IF PEEK M=63 OR PEEK M= 116
GOTO 35
LET Let
75 LET U(L)=PEER M-25+R
209 GOTO Sö
35 GOSUB 5090
110 PRINT
GOSUE 6506
120 IF G(1)=U (L-2)
THEN GOTO i568
125 GOSUB 29090
AND G2) zU tL
—
130 PRINT "7? ":Gl12:".";G(2)
132 PRINT
133 PRINT TAB 8."NO"
134 IF K-i THEN PRINT UtL-1);:
155 IF K=1 THEN GOTO 170
LET K=1
GOSUB 599
145 GOTO 128
GOSUB 500
PRINT 6113".
PRINT
PRINT TAB 6. "YES"
“NZL FOR NEL SERIES"
` THEN GOTO 26
“:61(2)
INPUT ";L-
INPUT Gti}
eee PRINT “ IN
INPUT G12>
RETURN
Dea Fe NU
PUT ";L:"TH NUMBE
Listing 2. Changes for 4K ROM.
20 aoe is RNO 1100)
30 =16426+RND 119
35 p: PEEK (H5 =6S THEN’ boro ze
SS IF PEER iM} =69 OR PEER (M3 =i
2 THEN GOTO S95
Z9 LET U (CL) -PEEK (M3 -28+R
1335 PRINT ."NO"
165 PRINT ,"YES”
blocks starting with Z which is used as a
flag to tell the computer where each block
begins.
Line 30 randomizes which block of data
is to be used. The computer then searches
for the beginning of the block in line 35.
A constant is added to the series to make
the program more challenging. The end
of each block is flagged by the Z of the
next block or by 118 (NEWLINE) which
is the end of the REM statement. The
series is printed on the screen except for
the last two numbers which the player
has to figure out.
The program is packed tightly in 1K
RAM on the ZX80 and requires over 1K
RAM on the ZX81. Memory is saved by
using keyboard commands in lines 170,
600, and 610. In this way the program
provides the maximum variety of series in
the small memory.
To exit the program, key in a unused
variable letter when asked for a number,
or key in a character when "N/L FOR
NEW SERIES" is printed.
Enter the program in Listing 1. If you
have the 4K ROM make the changes in
Listing 2 as you enter the program. Hit
RUN and ENTER, and stretch your arith-
: Fa
metic perceptions.
42,44,44,46,43
UT STH NUMBER”
STH NUHBEE
48.49,
INPUT
in ¡Str
¿5,48 , 42, dd dd 46,48,7? 58,52
NO
ZNPUTY STH NUMBER
SYNC Magazine
-81 SPACE RAIDERS"
AO BEEP OP MER TES“ PG
3.292 E 05 6E= 1.297 E 03
8:275: E 05- X =""5:222 E -05
1.182 E 07 Y=-2.574 E 05
4.780 E 06 Z= 5.692 E 06
The Federation has the remainder lock onto your
declared a state of all-out war, position...
leaving you in charge of the High speed graphics and
Starship Defiant: newest and custom ML math package
most advanced spacecraft provide the real time, accurate
known to man.. simulation of the above space
Soon, your experienced navigation and battle scenario.
guidance will bring you within You’ve never seen this kind of
range of the Klingon convoy. performance on your ZX81
Hundreds of stars flash by as before!
you check the status of your Only $19.95 for cassette,
Phasors, Shields, Masking, keyboard overlay, and manual
energy drain is tremendous, as
As you come into range N i RAD
Maneuvers!!! Space explodes
all around you as the first 959 East 460 South
Navigation, Scanning, and (shipping included). (Utah
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the target distance indicator
ticks slowly downward...
you set your cross-hairs on the
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Switch to Aft view!!! Evasive
Klingon ship disintegrates and Provo, UT 84601
ZX81 PERSONAL BANKING SYSTEM
WITH LOAD/SAVE DATAFILES
AT DOUBLE SPEED
Load the des ele in the normal way—enter, amend or delete your
transactions (ZX81 will automatically scan standing order file and post
any items due)—save the file of data onto cassette in 45 seconds—load
a different datafile into the same program, also in 45 seconds—enter
items, etc.—save datafile only onto cassette (45 seconds)—repeat
operation for any number of accounts.
Absolutely no need to save program, as all information is held in data-
files. Very easy to use—unlike other bank accounts. Requires a mini-
mum of 16K RAM—can use much more (no modification required).
On Demonstration at the next ZX Micro Fair.
The personal Banking System also includes the following features—
Full page detailed Bank Account, dual display (or printout).
Automatic generation of standing orders on due dates.
Validation of all entries.
Correct any item previously entered. (Single/Multiple field correc-
tion)
Enter an item (previously omitted) in the correct date order of the
account.
Single key operation. Utilises a M/C keyboard scan.
Search for any item or items by cheque number, description or
amount—display (and printout if required) with totals.
Continuous display of statement extract, continually updated dur-
ing input of entry.
File of standing order details can be displayed, printed, added to,
cancelled and amended.
Detailed User Manual.
After sales maintenance.
Send £9.95 ($20) incl. for cassette and users manual to J.P. Gibbons
A.I.B., 14 Avalon Road, Orpington, Kent, BR6 9AX, England. (Send
large S.A.E. for details).
There are only two suppliers of supported ZX81 software, this is one of
them. Be sure to include your name and address.
Coming soon: Bank Reconciliation Module—a separate program on
cassette that utilises data supplied by the main program
(S.A.E. for full details).
The only expandable system for the ZX81.
The Personal Banking System is also available from the Buffer Shop,
Streatham, London and Branches of the Computer Bookshop Group,
full maintenance still available.
from |
Y | | UM i E U rÀ Y the leaders
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y
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Other great ZX games and add-ons
from Mikro-Gen: A/D Converter Board
Space Invaders Lets you connect analogue
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ever-increasing rate of play inputs. Suitable for many other
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Breakout and itimproves RAM pack
with seven bat angles to make stability!
it really difficult ONLY $36.95
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positively addictive Connect via our A/D Board-
makes your ZX81 a true
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The original- and still the best! machine
S 's Castle ONLY $18.95 EACH
orcerer's i
takes youl into a world of Disassembler/Monitor
learning machine code-
Above games all supplied on cassette. lets you enter and run your
with library case: own code
$7.95 each (ZX Chess $12.95) ONLY $7.95
Write for full details of the Mikro-Gen range of programs and add-ons,
available from local stockists or direct from the manufacturers (please make
cheques/PO's payable to Mikro-Gen and add $1.90 postage for software,
$3.50 for hardware Suppliers of Software to Sinclair
MIR UE
24 Agar Crescent Bracknell Berks RG12 2BK
Tel: Bracknell (0344) 27317
Supplied on cassette,
with library case
8K ROM
1K RAM
Solving Implicit Functions on the ZX81
Basil Wentworth
Solving arithmetic and algebraic prob-
lems on the ZX81 is easy when the
variable wanted is defined explicitly, that
is, if you know that Y = X **2+2*X, it
is easy to program:
10 INPUT X
20 LET Y= X**2+2*X
30 PRINT Y
Now you put in the values of X and let
the computer find the corresponding
values of Y.
The fun begins when the variable you
want is defined as an implicit function.
Suppose, for instance, you have a value
of Y for the above equation and you want
to find the corresponding value of X. As
a practical example, let us define a rec-
tangle with an area of 15 square feet
subject to the constraint that the length
will be two feet greater than the width.
This would give you the exact equation
shown above, i.e., 15 = X * (X + 2) or 15
S ALE 2* X.
This is a little hard to program. Just try
telling your computer to LET 15 = X ** 2
EZEK,
In your high school algebra class you
learned some fairly easy ways to solve a
quadratic equation and that is what we
have here—if you remember them. But
what is the use of having a computer if
you are going to solve the problem by the
old horse-work techniques? Or, suppose,
you get something a bit more complicated
ENEAS 3*3 2 Ar OT,
perhaps, Y = X * SIN X. Or, Y = (e ** X)
* SIN X. It is a little harder to solve these.
The computer can handle problems of
this kind by making a series of successive
approximations: try out any value of X,
and see if it gives the Y you want; if it
does not, then try another value of X.
Basil Wentworth, 1413 Elliston Dr. Bloomington,
IN 47401.
58
This is the sort of thing that a computer
does beautifully, but you will want to give
it a little guidance. If you keep pulling X’s
out of the hat, you may never hit on the
right one; in fact, you may not even know
how close you are to being right. So you
want to find a systematic way of zeroing
in on the right value of X.
Figure 1. Graph of Y —X**3-9*X**2 -26*X
30
10
X142
SYNC Magazine
STOCK MARKET
PRICE p
ANALYSIS
HELP! for the
Small Investor
Now SINCLAIR ZX-81 (16K) owners can do what the professional market traders
do — use a computer to predict price direction. This program tracks up to six stocks,
averages, or commodities, and produces graphs and uses technical indicators to
help you make trades.
Technical analysis is based on two ideas: first, that the market, like the rest of
human behavior, repeats itself; and second, that there are professionals and in-
siders who know what the market is going to do before everyone else does, and who
place trades in a way that is hardly noticeable. TECHNICAL ANALYSIS attempts to
read the price action and volume figures to determine whether predicable patterns
are developing, and what the professionals are doing.
Professional traders have been using computers to make this kind of analysis for
years, because the manipulation of the data is very complicated and time-
consuming. With this program, you let the computer do the work, and its signals
become a powerful investment tool.
The program makes GRAPHS of the daily prices, of two moving averages, and of
a volume indicator. A booklet that comes with the program helps you learn what to
look for.
The program does an ANALYSIS to signal trend-formation and tum-arounds. It
gives a score for each indicator, and a total score, to help you see whether there is
confirmation among the signals.
USE THIS TO TRADE STOCKS, OPTIONS, AND THE NEW STOCK INDEX
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This gives POWER TO THE SMALL INVESTOR!
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Personal Management
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ZK-PARTY GAMES $9.95
Five Games for Hours of Party Fun.
Includes Charades (500 topics), Password (500 words),
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PARTY GAMES FOR CONSENTING ADULTS $14.95
Contains five games designed to entertain a gathering
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ZK FOOTBALL $12.95
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A good way to introduce your three-six year old to com-
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ARITHMETIC BASEBALL $9.95
An entertaining educational program where children
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range from simple counting to trig. Correct answers
result in hits according to relative difficulty.
HOME MANAGER $12.95
This menu driven program stores info on 50 families
(enough for most) on each cassette. Names, address,
phone, and four lines of miscellaneous data (up to 8
important dates). Sort on names or dates. Also includes
printer output for address labels or complete files.
WE OFFER A COMPELTE LINE FOR EDUCA-
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STATS IN A FLASH
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60
Linear Interpolation
The method for doing this is called
Linear Interpolation. Look at Figure 1 for
a moment. Suppose that the solid curve
shows the relationship between X and Y
and that the dotted line indicates the
value of Y that you are interested in. The
value of X that yields this Y is found, of
course, right beneath the point at which
the dotted line hits the curve —somewhere
between X1 and X2.
So select X1 and X2 as first approx-
imations, find what values of Y1 and Y2
they correspond to, and then go for
another estimated value of X according
to what Y1 and Y2 tell you. The adjust-
ment in X will not be strictly proportional
to the error in Y unless the curve is a
straight line in this region, but a pro-
portional correction will still get you
closer than you were, although on rare
occasions you will come across a function
that defies solution this way. Then use
the new value of X as the approximate
solution, and go through the process
again, and again, if necessary, until you
have reached the degree of accuracy you
want.
Choosing your first X1 and X2 so that
Y1 and Y2 surround the value is not
usually imperative, but this can be helpful.
In most cases, any two arbitrary approx-
imations (as long as they are equal to
each other) will suffice although some
take longer to run than others.
Listing 1 contains the program to use.
Type it in; press RUN and ENTER. The
computer will ask you to enter the state-
ment of the equation as Line 40. For
example, the equation cited above would
be entered as
40 LET Y=X**2+2*X
Then RUN 60 as the program instructs.
The computer then tells you to enter a
couple of guesses for X, as well as the
target value for Y.
Then, as instructed, enter some toler-
ance figure to define the degree of
accuracy that you want in the answer. Be
realistic. If you ask for O tolerance, the
computer will run all night seeking the
impossible. If you specify 10% the com-
puter will probably come a lot closer than
10%. If you call for .01%, the error seems
— Listing 1. Implicit Functions (8K ROM).
e 19 PRINT "ENTER ""
20 PRINT
30 PRINT “THEN RUN 6068”
su EET
T
70 PRINT "ENTER Y"
Yo
40 LET Y=F £
NT
i gii "ENTER FIRST APPROXI:
120 INPUT Xi
159 LE oa: SECOND APPROXI
250 LET Yi=
260 T X=X2
270 GOSUB 40
230 Y2=Y
4 hard LET X321X1-X2) &fYQ-vY 2) vr ivi
2 en
300 LET X1=X2
310 LET X2=X3 yd
320 IF ABS (100r(X1-XZ2) X1 >T 3
HEN GOTO 210
330 PRINT "X = ";X2
usually to fall in the range of .001% or
less. This is close enough for most practi-
cal purposes. In fact, you may want to
“hard-write” (as an analogy with “hard-
wire") a tolerance limit of .01% or .001%
instead of entering it each time.
Limitations
This technique has one limitation that
may be serious in some instances. Many
equations have two or more solutions,
but this approach will give you only one
of them. In the example given, the two
solutions are: X — 3 and X = -5. In the
practical cases, you are interested only in
the positive values since it is rather
difficult to lay off a length of -5 feet. And,
if you started out with positive values for
your approximations to X, the computer
will give you the positive answer, but you
run into trouble if more than one solution
is realistic.
The curve shown in Figure 1, for
example, represents the equation Y — X
** 3-0* X ** ) 4-26 * X. If Y = 24, the
equation has three positive roots: 2, 3,
and 4. This routine will give one or
another of them according to the approx-
imate values chosen as the points of
departure. If it were not for this factor,
entering “hard-write” values for X1 and
X2 in lines 120 and 150 would be
tempting.
SYNC Magazine
Another caution: do not make your
first approximations too small. Above all,
do not use zero. Even if you expect your
answer to be zero, it is better to start with
numbers like 1 or 2 to reduce the possi-
bility of running into numbers too big for
the computer to handle in line 260.
One other danger to watch out for is in
the handling of negative numbers.
Remember that the ZX81 is not able to
raise negative numbers to powers. I sus-
pect that this is so because the computer
uses logarithms in the process, and the
logarithm of a negative number baffles
computer and human alike. If this danger
appears to be imminent, it can be avoided
by the following substitutions:
For even-numbered exponents, replace
X ** n by (ABS X) ** n.
For odd-numbered exponents, replace
X ** n by SGN X * (ABS X) ** n.
Remember that it is very, very likely
that you will run into negative numbers
when you use trigonometric functions.
The same strategem will work with them.
For even-numbered exponents, use
(ABS (SIN X)) ** n.
For odd-numbered exponents, use SGN
(SIN X) * (ABS (SIN X)) ** n.
The program can be translated to the
4K ROM by making the following
change:
10 PRINT “ENTER#”;CHR$(212);“#40
LET Y=F(X)”;¡CHR$(212)
However, the program will lose some
of its appeal because of the lack of
floating point arithmetic. The answers will
be in whole numbers so the closeness of
the approximations will be lost.
One final limitation is that this routine
will not give imaginary roots, i.e., square
roots of negative numbers, designated by
mathematicians as i and by engineers as j.
But you have little chance of running into
these unless you are working with AC
power or electronic circuits.
One final caution, remember that the
ZX81 gives you the arguments of trigono-
metric functions in radians. If you want
degrees, multiply the radian value by
180/PI. (Ed. —See the article “Degrees,
Grads, and Radians" elsewhere in this
issue.)
September/October 1982
Extend your ZX81 System:
*or TIMEX
1000
Add Memory that won't Forget!
^ ADD YOUR OWN SYSTEM UTILITIES
^ BUILD UP A LIBRARY OF MACHINE
LANGUAGE SUBROUTINES
^ UP TO 8K NONVOLATILE RAM * d
^ USE HM6116P CMOS RAM
OR 2716/2732 EPROM
^ COMPATIBLE WITH .— ^
16K RAM PACKS — 77
di
This memory board is designed to fill the transparent 8K
block of memory (from 8 to 16K) in a ZX81-16K system.
The use of HM6116P 2K CMOS RAM memory IC's with
their own reserve power supply means that routines stored
in the RAM are nonvolatile — the RAM retains its memory
even when the ZX81 is switched off or reset. Moreover, be-
ing RAM, the routines you store in the memory are easily
modified.
With this board it's no longer necessary to place your
machine language routines in REM statements, in string
variables, or beyond RAMTOP. You can build up a resident
library of machine utilities for use by your BASIC system.
un ne
a A
AT conver, 7
e p
p
4
yz
Complete step-by-step instructions in a 14 page manual
make assembly of the board easy. Construction takes be-
tween one and two hours. The kit (pictured above) is com-
plete with a silkscreened solder-masked printed circuit
board, all capacitors, resistors, transistors, sockets, con-
nectors, integrated circuits, and the lithium cell. The board
is supplied with one 2K CMOS 6116P-3 RAM — it will ac-
comodate three more for a total of 8K.
Send check or money order for $29.95 plus $1.95 shipping
and handling to the address below. The printed circuit
board with the instruction manual is available separately
for $15.00 post paid.
HUNTER, 1630 FOREST HILLS DRIVE, OKEMOS, MICHIGAN 48864 H
ZX81 TIMEX MICROACE
CRASH NOT. WANT NOT.
Have you had unexplainable system crashes? Lost
programs due to brownouts or power failures? Or
just plain tripped over your electric cord?
If so, you need an uninterruptable power supply.
ZX80
UPSYSTEMS is a battery powered backup system
that kicks in automatically as soon as its sensors
detect a drop in voltage coming from your power
supply. Your system keeps on ticking.
Simple to install and use. Just plug your power cord
into UPS and plug UPS into your system and you
are ready for any power glitch or failure. (Additional
cord included).
All systems include on/off/reset switch for your
convenience (you no longer have to unplug your
computer to reset it). All systems are compact, ap-
prox. 13 cm x 7 cm x 4 cm (5Vs" x 2%" x 15”).
UPS-1
Economy system, uses 2-9 volt alkaline
batteries (not included). $14.95 + $2.00
shipping, handling & insurance.
UPS-1M Same as UPS-1 except it includes a Pro-
gram Loading Monitor to solve your tape
loading problems. $19.95 + $2.00 S, H&l.
UPS-2 NiCd system that recharges itself auto-
matically (NiCd batteries included). $29.95
+ $3.00 S, H&l.
UPS-2M Same as UPS-2 except it includes a PLM.
$34.95 + $4.00 S, H&l.
90 Day Guarantee on Parts and Labor.
Check or money order payable to: UPSYSTEMS.
Foreign orders add $1.00.
UPSYSTEMS ,
RA BANKS
5800 HOLLISTER
DEPT 1901
HOU TX 77040
ARTIFICIAL INTELLIGENCE
FOR THE ZX81?
YES!
SYNCZX is an artificial intelligence
program with natural language capabili-
ties for the ZX81 with 16K RAM, avail-
able from Frog Software.
SYNCZX will talk to you in ENGLISH/
NO MENUS. You can use SYNCZX to
balance your checkbook or you can re-
program SYNCZX to do anything you
would like. However you do not need
programming skills to use SYNCZX as
is. Even a child can use SYNCZX be-
cause it is easy to read and understand,
talking to you in simple English.
SYNCZX even remembers the people
who use it! 16K cassette with manual
only $6.95 plus $1.50 postage & han-
dling.
ALSO AVAILABLE
PERSONAL COMPUTING PACKAGE
7 programs. Graphs (1K), Appoint-
ment book (16K), Checkbook (16K) and
Three Games (1K), etc . . . All 7 for only
$1.95 plus .70€ postage & handling.
Send to:
Frog Software
Box 95
Glenmont, New York 12077
(518) 465-6552
61
BOLEX: Beginner's Ohm's
Law EXercises
Ohm's Law
George Simon Ohm (1787-1854) was a
German schoolmaster who studied the
electric circuit and determined the
relationship of voltage, the electromotive
force (E); current, the intensity of elec-
tron flow (1); and resistance, the oppo-
sition to electron flow (R). The results of
his experiments were expressed in the
equation E=IR which can also be expres-
sed as I=E/R and R=E/I.
To those outside the field of electricity,
this equation, now called Ohm’s law, may
not seem very impressive, but it plays a
very important role in the design and
creation of such everyday wonders as
electric lights, telephones, toasters, TVs,
car starters, refrigerators, and computers.
Before Ohm’s work, unknown values of
voltage, current, or resistance had been
difficult, even impossible, to find experi-
mentally. However, these unknown cir-
cuit values can now be found quickly and
accurately by mathmatical computation
from Ohm’s equation. Despite this con-
tribution of great importance to electrical
science, Ohm lost his teaching job.
In addition to voltage, current, and
resistance the electric circuit includes a
fourth element: wattage, the measure of
power consumption. Wattage is found by
another equation: P=IE, in which P
stands for watts. Thus, watts equal current
times voltage. Notice that the power
equation and Ohm’s equations all have
the terms I and E in common. Knowing
how mathematics handles equations with
common terms, we can see the expanded
versions in Figure 1.
BOLEX
BOLEX is a program that solves these
equations two at a time. Enter the pro-
Ray Stadta, 120 Calle Cuervo, San Clemente, CA
92672. Translated to 8K ROM by James
Grosjean.
62
Ray Stadta
Figure 1. Ohm's Law Variations.
gram into your computer, hit RUN and
NEWLINE. Four prompts will appear on
your screen: amps, volts, ohms, and watts.
Type in a value for one, hit NEWLINE.
Continue until the values have been
entered. With two values you will be able
to find the other two. Try the following
sample runs:
1) An appliance circuit has a current
rating of 9 amps with 120 volts applied.
What is the value of resistance in ohms
and the power consumed in watts? Input:
amps: 9; volts: 120; ohms: 0; watts: 0.
The program finds the ohms and watts by
solving the equations: R=E/I and P=IE.
2) How much current is drawn and how
many watts are consumed by a 120 volt
heating unit with 14 ohms resistance?
Input: amps: 0; volts: 120; ohms: 14;
watts: 0. The amps and watts are found
by solving: I=E/R and P=IE or
P=E*E/R where E is small enough not to
cause an arithmetic overflow.
3) How much amperage and resistance
is in the circuit of an appliance that uses
1625 watts plugged into 120 volts? Input:
amps: 0; volts: 120; ohms:0; watts: 1625.
The program solves: I=P/E and
R=E*E/P.
4) A high-voltage circuit draws 5 amps
with a known resistance of 450 ohms.
Find the watts and volts. Input: amps: 5;
volts: 0; ohms: 450; watts: 0. The program
solves: ESIR and PSIE.
37541
AMPS (ti
L a ove
M
VOLTS (E)
OHMS tR)
WATTS (iP) 8
97641 AMPS
8.13
Machine Limitations
The 4K ROM has three limitations for
the full use of the formulas. First, it
functions only with whole number arith-
metic. However, the program in Listing 2
includes routines for coaxing decimals
from the ZX80 for the amps computation
in the following lines:
210-240: division to one decimal place.
300-370: division to three decimal
places.
430-440: multiplication of a 3-place
decimal with accuracy near enough to
100% for the purposes of this program.
Second, the 4K ROM does not have
the SQR function so again a routine is
included to do this in lines 150-230.
However, this gives roots only as whole
numbers.
Third, in order to provide whole num-
bers the 4K ROM always rounds off the
number by rounding down. This means
that computations involving decimal
places on the 4K ROM will not have the
accuracy that the 8K ROM provides.
As you use this program to work out
electric current problems, remember that
the Sinclair is a beginner, too, and has a
limited range. If you get carried away
trying to figure how many watts are used
to light up Yankee Stadium for a night
game, be ready for an overflow error code
(6).
By the way, six years after Ohm was
fired, he got recognition and a better job
at the University of Munich.
SYNC Magazine
LIGHT PEN UNDER $70
¿pat LIGHT PEN
Light Pen for ZX81. Cassette included. $69.95
Control Board for 8 devices $49.95
Character Generator $59.95
6K memory (Internal) $49.95
mail to:
ZODEX east hill,
oakham, ma. 01068
NEW 8K/16K
FROM HAY MARKET
ZX-BLACK BOX
ZX-CONCENTRATION
Easy To Play
Educational & Fun
Playable By 1 or 2
Cassette & Documentation
Auto Run Features
Playing Boards Displayed
Black Box $10.95 A
Concentration $8.95 Florida Res.
Add 5% Tax
DOWNSWAY
ELECTRONICS (UK) LTD
MORE MEMORY FOR THE
ZX81/TIMEX 1000
16K — only $49.95 64K — just $119.95
Prices include shipping and handling
Downsway Electronics was one of the first
manufacturers of add-on memories for the
ZX81, and is a market leader in Britain and
other countries.
The Downsway 64K Memory slots directly
on to the computer, without needing an
additional power supply or adding any extra
load to the internal 5v regulator, and gives a
further 56K of available memory.
^... neat, small... fits very firmly... good
value" ZX Computing "fits perfectly with the
style of the ZX81 ... very well made...a very
worthwhile addition to any ZX81". Popular
Computing Weekly.
The Downsway 16K RAM Pack is built to
the same high standards of quality,
performance and reliability for users who
don't need a full 64K.
Both memories incorporate a top quality gold plated
edge connector, and come complete with a special
foam cushion strip for extra stability, plus comprehensive
instructions and a full six-month warranty. Printer compat-
ible, with “low profile" styling (both memories measure
only 3 x 2 x 1 in).
DEALER/DISTRIBUTOR
ENQUIRIES WELCOME
Send check or International Money Order to:
Downsway Electronics (UK) Ltd
Dept. S, Downsway House, Epsom Road,
Ashtead, Surrey, England
___ Figure 2. Ohm’s Law Program (4K ROM).___
10 FRINT "AMES (1) HH" s
ZO INPUT I
AO FERUNT
40 PRINT "VOLTS (E)#";5
SOCINPUT E
60 FRINT E
YO- FRINES"
80 INFUT R
7D) FRINT- R
16) BRINT w« P > i2
BUT A COMPLEX SIMULATION OF FOUR MILITARY- INDUSTRIAL ; pe eect Bede SONO
ECONOMIES LOCKED IN A DEADLY STRUGGLE FOR SURVIVAL. 120 PRINT F
ONE TO FOUR PLAYERS COMPETE WITH EACH OTHER AND/OR 120 FRINT
149 GO TO ABS (150% (I+E=0)+260XK (
NOT ANOTHER TOY
OHMS (FR) HH";
THE COMPUTER. BALANCE OF POWER DEPENDS S SR
UPON [+R=0) AEROX ([4+P=0) +450%* (E+R=0) +4
SKILL IN DEVELOPING RESOURCES, USE OF ESPIONAGE, gox (E+E sO) +35 10k (R+F=0) )
EXPLOITATION OF ALLIANCES, AND UTILIZATION OF MILITARY 150 LET Hz192
160 LET L=0
170. LEP ESL HJ 72
180 LET E=(PXR)/E
190 IF K-E THEN GO TO 240
POTENTIAL. REQUIRES ZX81 WITH 8K ROM AND 16K RAM.
dig ede 200 IF H-L«2 THEN GO TO 240
O 210 IF K«E THEN LET H*E
— brat 220 IF NOT K«E THEN LET L=E
290 607 TD.170
OIDRIOMIORCHORCWAR] 00
GO TO 330
Send $14 (plus $1 for shipping) to: STRATAGEM CYBERNETICS, INC., LET I=F/E
286 Corbin Place, 2E, Brooklyn, New York 11235. \
LET XzP-IXE
LET Y=lOxXx/E
BI ee clu :
N CIT s y uv ro
LET R=EXE/F
er oe U DIN ie E PERE pus
LET I=E/R
LET Mi=E-Ixk
LET Di=10x*xM1/R
280 LET M2=10xM1-D1xR
a 390 LET D2-10XM2/R
400 LET M3=10XM2-D2XR
410 LET Di=10xM3/R
420 PRINT I;:".";D1;D25 D; "AMPS"
4230 LET FzCODIX100-D2X10-D3)/10)
kE/100+1XE
440 60 TO 540
450 LET ExF/I
460 LET R=E/T
470 GO TO Sao
480 LET E-IXR
4930 LET FIXE
DOO. GO: 10: 539
710. LET^RSEZT
S20 LET FIXE
S20 FRINT I; "#AMFS"
S40 FRINT Ex "VOLTS"
S50 PRINT Rs; "#OHMS”
360 PRINT Fs "HWATTS"
PRINT Dp". "3 Ys "HAMPS"
ne
Da Valea Woes
EXPANSION BOARD
Buffered Bus/Development Board for
marketed and user built peripherals.
Offers significant yet inexpensive access to ZX81 hardware.
All lines from
computer port
are on bus & in
same order.
Buffered Data,
Control & Address
lines. Data bus
is two-way.
Gold plated €
fingers.
ON OR ae is
MA SI
Optional &
volt reg.
ener Keen ane Knennn s
Circuitry
gives access
to addresses
8K to 16K for
memory or
memory mapped 1/0.
Two types of — —Figure 3. Ohm’s Law Program
connectors:
Aso".
"Vw ew wom twv Mw wwe rw
10 PRINT “AMPS (13 TR
38 PRINT I
9 chips needed; 40 PRINT “VOLTS i£! "i
all parts are So INPUT E
Fastens to ZX81. standard.
Finest quality board.
Plated thru holes,
solder mask, legend.
Improved Model:
Bare Board $40*
With connector to port
and complete documentation.
K it $65* Includes
6 connectors, 9 chips, sockets
and other parts.
*Add $3 for ship & hndl.
Calif. res add 6% tax.
To order send check or M.O. to: a
( omputer i
301 16 th Ave
San Francisco, CA
130 PRINT
148 GOTO 1158%+ (1+E-=2) +190+ (1+R=
9) +218021+P=9) +2404 (E+R=0) +2707% 1
E+P=9) +300% ([R+4P=0B))
150 LET EISE (PER)
PROMPT DELIVERY.
HUNDREDS OF SATISFIED
USERS.
Please send stamp
for more info.
UHF MODULATOR $15
CLEANING TV DISPLAY
ontinuum
(415) 752 6294
329 PRINT I; " AMPS”?
339 PRINT E." VOLTS”
340 PRINT R;" OHMS"
350 PRINT P," WATTS”
94118
64 SYNC Magazine
SOFTWARE
DR. FLOYD
Psychoanalysis by computer? - well,
not quite but Dr. Floyd will carry on a
conversation with you using
psychoanalytic techniques giving the
appearance of artificial intelligence.
Requires 16K RAM. $10.95
GRAPHICS PAC |
An introduction to Sinclair graphics -
includes a 1K Line Doodler, a 16K
Super Line Doodler, several random
drawing programs and a Screen For-
matter. Kids will love all of them. The
screen formatter will satisfy serious
a A el rin a cn
use but simpler sections will run with | TO ORDER:
ZX81 x TS1 000 HARDWARE
SIN16
5459 16K RAM
This RAM plug-in allows the user to run
virtually all programs written for the ZX81
or TS1000. Completely assembled 4
tested
$4 3 95 SUPER SIN64
5 64K RAM
This is the maximum directly address-
able RAM that your ZX81 or TS1000 can
use - Memory is used as follows: 0-8K
Sinclair operating ROM. 8-16K switches in
or out of use. Used for assembly
language routines, memory mapped
peripherals. Contents are safe from NEW
and cassette (disc) loads thus allowing
progrom-to-program communications.
1 or 2K. $10.95 16-32K BASIC and assembly language
Send Check or MO user program area. 32-64K large data
WORD PLAY For the total + $4.00 S & H arrays & BASIC variables.
| Fun with words - 2 jargon generating Calif. residents add 6% tax. All hardware is completely compatable
programs for grown ups, 2 story or PHONE with Sinclair add-on products. Both
writers for children and a bonus 805/482-3604 RAMS use the mose reliable gold plated,
secret message program. Requires
16K. $9.95
bifurcated contact connector on the
market.
10 day return privilege on all hardware-90
All software is on high quality cassettes For credit card orders, include all day parts and labor warranty-inexpensive
and is replacement guaranteed. info on card. extended service contract is available-
PROPOS TECHNOLOG
ZX-FORTH
Now you can have the SPEED and POWER of com-
puters costing hundreds or even thousands of dollars
more inside your ZX81. FORTH is now available on
cassette for the 16K ZX81. EASIER to learn than BASIC
and the most powerful language available for the ZX81
10 TO 20 times FASTER than BASIC and typically uses
less than HALF the amount of RAM space needed by
an average BASIC program. Includes extentions for
speedy graphics handling, as well as basic data han-
dling functions. Sample programs written in FORTH in-
cluded at no extra charge are: Scratch pad, a simple
word processor, Breakforth and Arcade-type game.
Also included is a complete bibliography and informa-
tion about fig-FORTH, the international FORTH users
group.
Find out why FORTH is gaining worldwide support as
the state of the software art and have fun learning about
computers the fast and easy way.
STRATOS CORPORATION
1451 N. UNION STREET
MIDDLETOWN, PA 17057
ZX-FORTH 16K CASSETTE $34.95
Add $2.00 shipping and handling.
Add $7.00 shipping and handling for foreign orders.
WE SERVICE WHAT WE SELL.
350 N. Lantana Ave., Suite 821 + Camarillo, CA 93010
LTEXT AND ZTEXT
ZX81 WORD PROCESSORS
lower case characters
on the ZX printer !!
$14.95
Plus $2.00
Airmail Postage
No longer need you be confined to space games, battleships and the like. With these
programs your ZX81 becomes a viable commercial machine. ZTEXT (upper case
characters only) and LTEXT (upper and lower case characters) are word processors which
incorporate a text editor and a formatter/printer. The text editor allows you to type test in
and edit it. The formatter/ printer takes the text and sends it to be screen or ZX printer,
justifying it and formatting according to commands embedded in the text. Included in the
range of commands are such useful operations as string search, string replacement and a
merge facility enabling a skeleton document to be filled with variable information. LTEXT
caters for both upper and lower case characters. No, that is not a misprint. By utilising the
_ high resolution graphics feature of the ZX printer Graham Asher has built a complete set of
lower case characters. These program come complete with a detailed manual.
Send $2.00 (redeemable against first order) for full catalogue
and FREE listing. Please state ZX81 on order.
All prices include VAT and P&P available from
Oasis Software, 20 Canterbury Close, Worle,
Weston Super Mare, England
Dealer inquiries invited
a vo rara —
muli 24 HOURS A DAY SCIF TLIARE_
Repeat Key Option George R. Ingle
Ed.—A WORD OF CAUTION: Any
hardware project for your computer must
be approached with extreme caution.
SYNC cannot be responsible for any
problem that may arise from attempting
hardware projects. Obviously, any dam-
age to your computer can be costly in
time and money.
A repeat key option is relatively simple
to build and install. In addition to IC
sockets, wire, and a suitable mounting
board, one of each of the following parts
is required:
555 timer IC.
74LS244 octal non-inverting tri-state
bus driver.
100uF miniature electrolytic capacitor
rated 15v or greater.
1K ohm resistor rated 1/4 watt.
5 or 10K miniature POT.
SPDT miniature switch.
The steps in construction are as fol-
lows:
1) Connect all components. Lead
lengths and component placement are not
critical. Good soldering practices should
be followed, as usual. See Figure 1.
Figure 1: Typical Diode.
Anode Cathode
A C
Typical Diode
D1C-Diode 1 Cathode
D1A Diode 1 Anode
etc. for all connections
2) Carefully de-solder and remove the
eight 1n4148 diodes in series with the
keyboard contacts. These diodes are
soldered to the computer printed circuit
board in plated-through holes. You must
be very careful not to damage the signal
line connects to these holes. On the
Sinclair these diodes are numbered D3
through D10; on the MicroAce, D1
through D8.
3) Carefully solder the wires to the
diode holes as shown. Make sure that
solder flows through the holes and makes
a good connection.
4) Connect the chip grounds and 5v
pins to a place on the circuit board. Just
about any connection supplying the nec-
George R. Ingle, 24593 1/2 Monterey Ave., San
Bernadino, CA 92410.
66
essary voltages can be used except the 5v
input to the VHF/UHF modulator. This
would result in unwanted “noise” created
by the 555 timer being sent to the TV and
causing distortion in the display.
5) Install and connect the switch. This
switch allows you to select the repeat
function or to return the keyboard to its
normal operating state. The logic low
KBD signal can be tapped at pin 1 on IC
10 for the Sinclair or pin 1 on IC 11 for
the MicroAce. This keyboard signal,
when connected to the 74LS244 allows
normal operation of the keyboard. See
Figure 2.
6) Set the repeat rate or frequency by
adjusting the 5 or 10K POT. The repeat
rate selected will remain stable, but keep
in mind that the repeat rate will be slower
on a ZX81 or MicroAce equipped with
the video upgrade operated in the slow
mode since these machines insert addi-
tional delays generated by the retiming
character display frequency. Too high a
repeat rate will make you “outrun” the
keyboard scan frequency used by the Z80
during an IORQ and RD. This will not be
a problem since the rate at which this
Occurs is very difficult to follow with your
eyes!
Figure 2: Schematic for Keyboard Repeater.
Lr
555
_ r
erem
BORD o
100uF
1K
T5v —
AB A9 A10 All A12
DIC D2C D3C D4C DSC
To 74LS365/74LS367
Al3 Al4 AIS
D6C D7C = D8C
11 13 17
¡DE
El 12 7 5 3
19
1
KBD
Buffer enable -——— a e
Pin 20— t 5v
Pin 102GND
15
74LS244
SYNC Magazine
“Touch-A- Matic ", Power
At Your Finger Tips!
KOPAK'S TOUCH-A-MATIC'” gives you the power to type more accurately
and much faster. It requires no wires, no soldering. Comes with complete
instructions. It’s as easy as removing adhesive backing and pressing into
position. Positioning is easy. Once in position, you are ready for touch-
typing with ease.
Our unique vinyl-key-hold creation will guide your fingers to the correct
keys. Finally, touch-typing now possible with your Sinclair* or Micro-Ace*?.
This remarkable product, as well as other KOPAK items, are now available.
Call now to order through MC/Visa or send check/M.O. to Kopak Creations,
Inc.
KOPAK CREATIONS, INC.
TM Trademark of KOPAK Creations, Inc.
Sinclair* is a trademark of Sinclair* Research LTD. (212) 757-8698
MicroAce* is a trademark of MicroAce* Master Charge & Visa Accepted
$1.50 Handling Charge
Dept.SY1 448 West 55th Street, New York, NY 10019 (212) 757-8698
8K ROM
1K RAM
Degrees, Grads, and Radians
Alvin Lam
Listing 1: Radians to Degrees.
There are three methods of measuring 19 PRINT “RADIANS=" :
angles: degrees, grads, and radians. How 2@ INPUT R
ever, the ZX81 with all its new trigono- 25 arta Uit
metric functions can only measure angles Za prim? "pc
in radians. You can convert a measure- &à STOP
ment by any of the three methods to
either of the remaining in irs the Listing 2: Degrees to Radians.
few short programs given in the listings a a S 8 E
below. You may want to add a REM 2d EE Tog *
statement to identify each listing for use 38 PRINT D
in a program. 40 LET R=P1I:D-186
Type in the program you need. Hit EV CIE. “RADIANS =":
RUN and ENTER. One prompt will
appear on the screen, e.g., in Listing 1, A ee
RSDIANS=. Type ip the dumber of | A
radians you want converted to degrees 2% PRINT “RADEANS=",
=$ ENP E
and press ENTER. The answer wil 3a DINT p
appear. 40 LET G=652 .6561977<4R
50 PRINT "GEGDS-":G
606 STOF
Alvin Lam, 690 Sunset Pkwy., Novato, CA 94947.
COSMONICS
ZX81 HARDWARE/SOFTWARE EXTENTIONS
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CS 21 Software for TTL Serial Output Port. Provides cor-
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BRL icis se NE RN E Ver vi $10.00
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a rueda. 2 OA RI. RR (CI $10.00
*CH 21K 2 IC Serial Ouput Port Kit for ZX81 (complete
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nen Y. SOR RAMIS I HOS RON A REE aig EEA OS $15.00
CS 22 Software for Serial Input. Provides RS232 input tim-
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RN aes W oe Ree Ys yk Yee o $10.00
*CH 22 Complete Plans for ZX81 Serial Imput Port.
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timer (useful in cooking)
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All cassette software listed here requires a minimum
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*Note: Any modification made on the ZX81 may
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Please add $1.50 postage and handling with each
order.
ONLY $3.75*
Y
y?
Listing 4: Grads to Radians.
10 PRINT "CGRADS=":
20 INPUT G
ið LET A=6-63.661977?
SO PRINT “RADIANs="
50 STOP
Listing 5: Degrees to Grads.
10 PRINT "DEGREES=":
Listing 6: Grads to Degrees.
iQ PRINT "UZSBRADS-"U:
Anymore!
. Another great ZX-81« demonstration .ONLY
3. ANYPOINT PLOTTER—1K—Crunches any data to allow
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dollar draft payable to U.S. bank.)
PRACTICAL ZX-81 SOFTWARE
ZX-81 Not Just
For Games
ZX-PANDING, LTD., an American company, uses the tremendous
ZX-81= data handling capabilities to make our daily tasks easier. Programs
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written in BASIC to allow tailoring to your special needs.
1. YOUR SPECIAL DAY—1K—Good example of using succes-
sive equations to answer a practical question. Enter any date in history,
and ZX-81= will tell you the day of the week on which it occurred. Useful
in many fields and a great ZX-81« demonstration. ..... ONLY $3.75*
2. CLOCKS AND TIMERS—1K—A digital clock (standard or
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COSMONICS, Box 10358, San Jose, CA. 95157 «Y. (Foreign orders add $2.00 to cover air
NEWTON, NC 28658 costs. Your payment must be in a U.S.
Rounding Off with
Conditional Tests James E. Stauffer
We have all learned in plane geometry
classes the Pythagorean theorem: a
squared plus b squared equals c squared.
Thus, if we know two sides of a right
triangle, we can easily calculate the third.
Or can we?
My son pointed out a Basic program
for finding “Pythagorean triples” in his
geometry textbook (Jurgensen, Donnelly,
Maier, and Rising. Geometry. Boston:
Houghton Mifflin Co., 1978). These are
the solutions to a right triangle when all
three sides are positive integers. I trans-
lated the program into ZX81 Basic as
follows:
10 FOR A=1 TO 20
20 FOR B=A TO 20
30 LET C=SQR(A*A+B*B)
40 IF C< »INT C THEN GOTO 60
50 PRINT A;TAB 5;B;TAB 10;C
60 NEXT B
70 NEXT A
James E. Stauffer, 6076 Chinaberry Dr., Columbus,
OH 43213.
Then we ran the problem, and the
display appeared as follows:
8B ds I)
0/70
This result was a surprise. What had
happened to the famous 3, 4, 5 triangle,
let alone all the other solutions we were
sure were there? It was obvious from the
display that the program was working and
that it had exhausted all possible values
of A up to 20, stopping at line 70.
The problem had to be in the con-
ditional test in line 40 which says in effect,
“PRINT only solutions in which C is an
integer.” Some of the obvious solutions
must be failing the test.
We decided to see what was happening
by going to the immediate mode, i.e.,
entering text without line numbers, and
typed:
LET A=3
LET B=4
LET C=SQR(A*A+B*B)
PRINT C
The screen display showed 5, which is an
integer, or is it? Knowing that some
8K ROM
1K RAM
algorithms, such as SQR, produce round-
off errors, we next tried:
PRINT C-INT C
The number 1.8626452E-9 appeared.
Here was the problem. A tiny error,
outside the display range of the ZX81
had caused many solutions to fail the
conditional test of line 40, which demands
that INT C be exactly equal to C. The
solution then was to rewrite line 40 to
permit small errors in the SQR solution
for C:
40 IF C-INT C»0.000001 THEN GOTO
60
When we ran the problem with this
change, we got the following results:
0/70
These are the proper solutions for all
Pythagorean triples for sides A and B less
than or equal to 20.
ZX81 users must be prepared to accept
slight imperfections when the computer
is dealing with non-arithmetic functions.
The algorithms used are powerful, but
some round-off errors may be present. Ma
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September/October 1982
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WISCON // //
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69
8K ROM
1K RAM
Block Transfers: Horizontal Scrolling
on your 1K ZX81
A programming technique called block
transfers of memory adds new possibilities
for your programming and for taking
advantage of your computer's capabilities.
Although the technique involves the use
of machine language, this article assumes
only that you are familiar with the Sinclair
manual ZX61 BASIC Programming and
that you are willing to work with hexa-
decimal. Dr. Ian Logan' article, “An
Introduction to Machine Language”
(SYNC 1:6) is helpful, but not essential.
For some readers learning may be its
own reward. For those who want a more
concrete incentive, this article will show
how to modify Douglass D. Sharp's
LSCROLL routine (SYNC 2:2) for a 1K
machine. Using this routine, you will be
able to launch a fleet of jets, in formation,
across your TV screen ... that is, after a
little homework.
What is a Block Transfer?
We must begin by defining a block of
memory. This is the information held in a
set of sequential addresses in the memory
of the computer. The contents of a REM
statement, for example, constitute such a
block. A block transfer of this information
would write the contents of the block
into a different area of memory. That is,
the sequence is reproduced at a new
starting address. Furthermore, the original
sequence is not disturbed unless the
“source” and “destination” areas overlap.
RAMTOP
To use this programming technique,
we must first understand the systems
variable called RAMTOP. Reviewing the
information on RAMTOP in ZX81 Basic
Programming, Chapter 26, would be help-
ful at this point. The discussion below
draws on this chapter and supplements it.
John Scher, 222A Hamilton St., Cambridge, MA
02139.
70
John Scher
When you turn on the ZX81, it tests to
see how much memory it has to work
with and then stores the address of the
first non-existent byte for future ref-
erence. This address is called RAMTOP.
It is stored at addresses 16388 and 16389.
For example, if you have 1K RAM, type:
PRINT PEEK 16388+256*PEEK
16389
and ENTER. This will tell you that the
address of the first non-existent byte is
17408. This is RAMTOP.
You can change RAMTOP by
POKEing the appropriate values into
addresses 16388 and 16389 then typing
NEW and ENTER. For example, suppose
that you want to establish RAMTOP at
17388. You would type POKE 16388,236
and ENTER; then POKE 16389,67 and
ENTER, and then NEW and ENTER.
These values produce the new RAMTOP
address by the following calculation:
236+256*67=17388
This POKEing will fool the machine into
thinking that there is no usable memory
above RAMTOP (17388).
As a result nothing above that address
will be disturbed by the Basic system.
The area above RAMTOP is also undis-
turbed by LOADing a new program into
the machine. The usefulness of this area
cannot be overemphasized because it
gives the user a place to store machine
code, Basic data arrays, and other mem-
ory blocks. These are then available for
use in multiple Basic programs without
having to type in the machine code or
data each time you want to use it.
The only disadvantage of this area is
that it is not saved by SAVE. This is why
block transfers are so useful. They allow
the transfer of information from a SAVE-
able area of memory to one that is undis-
turbed during program LOADing.
A Basic Program for a Block Transfer
Figure 1 shows a block transfer pro-
gram in Basic. This program locates the
bytes, in this case X’s, in the REM state-
ment and transfers them to a new starting
address. The address of the first X in the
REM statement is 16514. Before using
such a program to place machine code
bytes above RAMTOP, you must first
reserve space above RAMTOP as we
have already discussed.
The bytes in Figure 1 could just as
easily be in an array or another Basic
variable. Either of these would be sim-
ilarly SAVEable, although locating the
starting address for a block transfer would
be a bit more difficult.
Figure 1. A Basic Program for
Block Transfer.
1 REM XXXXXXXXXX
10 FOR N=0 TO 9
20 POKE 17398+N,PEEK (16514+N)
30 NEXT N
The LDIR Instruction
Given that much of the work of a
computer is moving things from one
address to another, it is not surprising
that the Z80(A) microprocessor has a
command that can accomplish a block
transfer much more quickly and efficent-
ly than a Basic program like that in Figure
1. This is the “Repeating Block Load With
Increment” instruction, LDIR. The LDIR
instruction makes use of three register
pairs: BC, DE, and HL. Initially, the BC
register pair must hold the number of
bytes that you want to transfer, just like
the FOR-NEXT loop in Figure 1. The DE
pair holds the first address in the “destin-
ation” block of memory, and the HL pair
holds the first address in the “source”
block of memory. The LDIR instruction
SYNC Magazine
transfers the contents of the address held
in the HL pair to the address held in the
DE pair. Then it increments HL and DE
(i.e., adds 1) and decrements BC (i.e.,
subtracts 1). It then compares the BC
pair to zero, and, if BC is not equal to
zero, the instruction is repeated, other-
wise the next instruction is executed.
Although we will use LDIR in the
sample programs in this article, you
should know that LDIR has a cousin,
LDDR, which is similar except that it
decrements all three registers. You might
think about which of these two you would
use to transfer overlapping memory
blocks.
An Overview of the Process
At this point let me summarize what
we are going to do. We will enter a
machine code block transfer program
along with a sample machine code routine
to be transferred into the space above
RAMTOP. Then we will transfer this
block of memory to a SAVEable REM
statement. At this point, a few mod-
ifications will be made, and then we will
try out LSCROLL with a sample Basic
program. There are slightly easier ways
to achieve the same end result, but this
sequence will teach you the most.
A Machine Language Block Transfer
The first step in entering the machine
language block transfer program is to
reserve 184 bytes above RAMTOP by
typing POKE 16388,72 and ENTER, then
POKE 16389,67, and ENTER, and then
NEW and ENTER. Now that you have
reserved the necessary space above RAM-
TOP, enter the hex loading program
shown in Figure 2 (from Booth, “The
Game of Life Revisited,” SYNC 2:1, p.
20).
When you RUN this program, the
screen will prompt you for a byte in
hexadecimal. Refer now to Figure 3,
which lists the block transfer machine
code. Note that the first nine bytes (con-
tained in addresses 17224-17232) set up
the BC, DE, and HL register pairs (LD
stands for load) as discussed above. The
next two bytes perform the transfer, and
the last returns the computer to Basic.
Note that all addresses within an LD
instruction, for example, 4082h = 16514d,
are entered lower-order-byte first, higher-
order-byte second, in the same manner
used to change RAMTOP. Remember
that a 0 in a hexadecimal listing such as in
Figure 3, column 2, is always a zero and
never the letter O.
. Now that the screen is prompting you
for an entry, enter the bytes in Figure 3,
column 2 (i.e., type 01 and ENTER, then
B8 and ENTER, etc.). Then go directly to
Figure 4 without typing RUN and con-
tinue by entering the LSCROLL
sequence. The parentheses and asterisks
will be explained later. For now just
September/October 1982
Figure 2. Hex Loading Program.
LET V=-1
LET V=V+1
IF INT (V/10)*10=V THEN PRI
INPUT H$
IF H$="" THEN GOTO 240
PRINT H$; "#"
IF H$="END" THEN STOP
IF H$="/" THEN GOTO 310
290 POKE 17224+V,16*CODE (H$)+C
ODE (H$(2))-476
300 GOTO 210
390 LET V=V-1
320 GOTO 240
Figure 3. The Block Transfer
Machine Code.
Decimal Hex Instructions
Address Code
17224 01 LD BC,Xof bytes
17225 B8 00B8h=1 84d
17226: 00
iy ce. T1 UD DE, destination
170p be 4082h=16514d
17229 40
(250 al LD HL source
17231 48 4348h=17224d
17232 43
17233 ED LDIR(transfer)
17234 BO
17235. 09 RET breturn)
Figure 4. The LSCROLL Sequence.
17236-17407 ENTER the LSCROLL
sequence: 3A(FE.43)FE.16.DA(61
.43)3E.00.32(FE.43)3A(FF.43)D6.0
0.CA(71.43)FE.15.D2(71 .43)C3(76.
43)3E.16.32(FF.43)F5.3A(FF.43)47
.F1.3A(FE.43)80.FE.16.DA(95.43)2
6.00.2E.16.3A(FE.43)4F.06.00.ED.
42.7D.32(FF.43)ED.5B.0C.40.0E.FF
,F5.3A(FE.543)6F.F1.26.00.06.00.1
A.FE.76.CA(AF.43)13.C3(A5.43)0C.
A7 E5.ED.42.E1 .CA(BC.43)13.03(A5
.43)06.00.F5.3A(FF.43)4F.F1.05.D
8.5123. 78 FE. 766G2(07.43)E5.A7»
ED.52.2B.7D.4D.D6.00.E1 .C2(E0.43
)E5.D1.C3(F5.43) 3D.C2(E8.43)13.C
3(F1.43)06.00.0B.13.D5.E1.23.ED.
B0O.3E,00112.13.C1.0B,79.D6400.C2
(C4 .43)09.00300*
. Figure 5. Changes for Transfers from REM to
above RAMTOP.
Decimal Hex Code
Address Code Changes
16514 01
Instructions
16515 B8—AC-172d,change #bytes
16516 00-+00 ,no change
16517. 11
16518 82—.5lh- 84d,change dest.
16519 40=>43= 674,4354h=172364
16520. 24
16521 48—+8E=142d,change source
16522 43—»40= 64a,408Eh=165264
16523 ED
16524 BO
16525 C9
IF INT (V/50)*50=V THEN CLS
ignore them (i.e., type 3A and ENTER,
then FE and ENTER, then 43 and
ENTER, etc.). If you make a mistake
while entering this machine code, note
that line 280 in Figure 2 gives you a
backspace key, “/”. When you are done
entering the machine code in Figure 4,
type END and ENTER, and the loading
program will STOP. At this point you
should check to be sure that you did not
leave out a byte or two accidently by
typing PRINT PEEK 17405 and ENTER.
The number 201 should appear at the top
of your screen (201d = C9h). Congrat-
ulations if you have come this far without
leaving anything out!
Next, SAVE the hex loading program
for future use. Then type NEW and
ENTER to clear out the memory for the
REM statement that we will use as the
destination block of memory. Put the
computer into FAST mode to enter the
REM statement, otherwise it will take
forever. Type 1 REM and then 184 X’s, as
in Figure 1,and ENTER. You can change
back to SLOW mode now.
Transferring LSCROLL
Now you are ready for the block trans-
fer. Type RAND USR 17224 and ENTER.
The transfer will occur so fast that you
will think that you made a mistake. Type
ENTER again and you will see the first
few bytes of machine code in the REM
statement. If this does not occur you had
better PEEK a few addresses between
17224 and 17235 to look for mistakes.
Before you SAVE the REM statement,
a few changes must be made so that in
the future, when you LOAD the program,
the block transfer will work in the other
direction, that is, it will transfer
LSCROLL from the REM statement to
above RAMTOP. Also, the first twelve
bytes need not be transferred because
they make up the block transfer routine,
not the LSCROLL routine. Figure 5 shows
the changes you must make. Column 1
lists the addresses that the block transfer
machine code routine occupies in the
REM statement, and column 2 is identical
to column 2 in Figure 3 for comparison.
Column 3 gives the decimal values which
must be POKEd in. Type POKE
16515,172 and ENTER, then POKE
16518,84 and ENTER, etc. until you have
POKEd all five changes in. Now SAVE
“LSCROLL”.
In the future, when you want to use
LSCROLL, reserve 172 bytes above
RAMTOP (POKE 16388,84; POKE
16389,67; | NEW), then LOAD
“LSCROLL” and transfer it to the space
above RAMTOP by typing RAND 16514.
In fact, you should do this now to reclaim
the twelve bytes of memory above RAM-
TOP that were needed before to make
the block transfer to the REM statement.
You will need all the memory available
for the sample Basic program in Figure 6.
71
Using LSCROLL from above RAMTOP
Once you have LSCROLL above RAM-
TOP, type NEW and ENTER to get rid of
the REM statement. Now you have
enough space to enter the Rockets pro-
gram in Figure 6. Note that the Rockets
program POKES three addresses in the
LSCROLL routine, 17394, 17406, and
17407. These addresses correspond to the
Figure 6. Rockets Program Listing.
1 REM ROCKETS
4 PORE I73984,.14
20 PORE 174809, 1-M
30 PORE 174087,1+23m
35 FOR N=a Ta 32
10 RAND USR 17238
43 NEXT N
oe NEXT M
50 CLS
70 GOTO &
bytes in Figure 4 that are followed by
asterisks. The function of these addresses
is as follows:
17394 specifies the code for the char-
acter which will occupy the new spaces
created by LSCROLLing.
17406 specifies the line number at
which to begin LSCROLLing; POKE in a
number from 0 to 21; see ZX81 BASIC
Programming, p. 89.
17404 specifies the number of lines to
be LSCROLLed, including the first one;
POKE in a number from 1 to 22.
Add 1024 to these addresses if you have
2K RAM (see below). Rockets calls the
LSCROLL routine with the line 80 RAND
USR 17236 since the starting address of
the LSCROLL routine is 17236.
Now comes the moment of truth. RUN
Rockets. If you have come this far without
making a mistake, you will see a line of
jets form on the right side of the screen
and take off across the screen in for-
mation, leaving their contrails behind.
For More Than 1K RAM
Those with more than 1K RAM may
want to locate LSCROLL at a higher
starting address. For instance, if you have
added 1K for a total of 2K RAM, you
have an additional 1024 bytes. Therefore
you could move RAMTOP to 18260
(17236 + 1024) for the final run which
only requires 172 bytes. Do not forget
that the hex loading program requires
184 bytes above RAMTOP. You will have
to make these changes to move RAM-
TOP.
First, add 1024 to the following addres-
ses in the figures:
Figure 2: Line 290.
Figure 3: all addresses in column 1.
Figure 6: Rockets Program: all addres-
ses.
Next you must change some of the
machine code.
Figure 3, column 2: change the 9th
byte from 43 to 47.
Figure 5, column 3: 43 — 67d to 47 —
71d. Note that we have been adding 4 to
the higher-order-byte of a series of
addresses because 1024/256 — 4.
Figure 4: The parentheses contain
addresses of information or routines
within the LSCROLL program. For in-
stance, the first parenthesis (FE.43) con-
tains address 43FEh — 17406d. Add 4 to
the higher-order-byte, 43, in all the paren-
theses. Thus the first parenthesis should
read (FE.47). The program is ready for
use at the starting address, 18260.
If you have more than 2K, make sure
that you understand the changes sug-
gested for 2K users, then give the changes
best for your machine a try. One last
word of caution: look over the article and
write in the changes you will want to
make in the addresses in the text, as well
as the addresses referred to in the figures.
As you can see, LSCROLL is a superb
program in that it allows the user to chose
exactly which part of the screen to scroll.
You are now ready to try some of your
own programs with the LSCROLL rou-
tine. The program has many other virtues
that are detailed by the author, and I give
it the highest rating of any machine code
program that I have seen in SYNC. Fa
CONTENTS.
Detective,
Billiards,
Machine Code Programmer,
Call Back Routine,
File Text,
Animated Cylist,
Load & Save,
We can accept no responsibility
for any illegal use of these
programs.
Savi ae i ae saan sae arm ire a aac Nes
72
HE SAID YOU COULDN'T DO IT
WE DID IT!
REVOLUTION IN TEACHING PROGRAM TECHNIQUES
APPRECIATE THE REAL VALUE OF YOUR COMPUTER
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& Choice of School Districts Nationwide e
24-PAK
$ .59
$ .69
$ .89
Add Sound to
Your ZX81! $1.09
Sounder circuit fits pp
inside the ZX81. $ 20
NO cutting, "Cases recommended to protect sensitive cassettes.
soldering, |
or unsoldering. NOPD Bors ESS
a : $2.00 (12-pak) $3.00 (24-pak)
Circuit beeps when — Canadian shipping multiply by 2—
key inputs are #1 COMPUTER TAPE
accepted by the computer. IN THE USA!
Send $12.00 per unit Ert undue
plus $2.00 postage SUN
and handling 1-800-528-6050
(N.J. Residents add 596 Sales Tax) pter
" ext. 3005
KML Incorporated E dl
P.O. Box 1147 MICRO 80 INC.
2665 Buzby Road
Oak Harbor, WA 98277
— Distributors Wanted—
New Brunswick, N.J. 08903
FULLER FD SYSTEM $79.95
Professional Keyboard £ Case for Sinclair ZX81/TS-1000
The ZX8lfits inside.
The tough ABS injection moulded
plastic case measures 8" x 14" x 2%"
and hooks up to your ZX printed
circuit board in minutes. No technical
know how or soldering is required.
KEYBOARD LAYOUT:
All the Sinclair ZX81 keys are duplicated on our layout, with extra shift and new
line keys. The professional momentary action key switches have a guaranteed
life of 10% operations. The unit is fully built tested and comes complete with a
money back guarantee.
INSTALLATION MOTHERBOARD:
Simply unscrew the ZX printed circuit board from We also manufacture a mother board which allows
its case and screw it into the FD Case. expansion to the ZX memory and 1/0 facilities
WITHIN the case, as well as our power supply unit
and reset switch.
Fuller FD System 42 Keyboard & case 79.95
E
FD System Motherboard H2ngus pus E
de FD 16K. Memory Module 49.95
FD 64K. Memory Module 149.96
FD PSU 9 Volts at 2 amp. A
FD Shipping and Handling 6.00 a
Mail to FULLER MICRO SYSTEMS,
The ZX Centre, Sweeting Street, Liverpool 2. England, U.K.
MS Cy MASON edm n Cerny VE ae
ay
A
EN
4K ROM m:
2K RAM son |
: rmm manne
8 sell \
0 ES : ix
ics
|
b
Chase
Kenneth Yu
Chase is a game of survival. The object
is to survive as long as you can. You are
set in a playing field, shown as a 20x10
block on your TV screen, surrounded by a
lethal fence. Mines are scattered about in
the field. You are being chased by five
robots which will move straight toward
you by means of their unerring sensors.
You must destroy them before they destroy
you; however, your only weapon is the
minefield itself. Thus you must maneuver
so that the mines will destroy the pursuing
robots. But, beware! You also can be
destroyed by touching the mines or the
fence. Your energy goes up by one as each
robot is destroyed. “H.S.” means the highest
score in previous games. Staying alive means
that you must destroy as many robots as
possible and hence beat the highest score.
When your energy is higher than the H.S.
shown, your energy will become the highest
score in the next game. (At this point you
may want to save the program again with
the new high score.) If you are successful
in destroying the five robots, you will be
transported to another 20x10 field with a
new mine configuration and five more
robots chasing you.
Because of the limited space, this program
is a hybrid of machine language and Basic.
7
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¡A —
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You control your movements by pressing
the number keys according to the following
diagram:
Directions:
1) Enter Listing 1, lines 1-660. At this
point SAVE the program and SAVE it
frequently from here on.
2) From this point on do not press RUN,
CLEAR, HOME, or LIST without a line
number.
3) Type in Listing 2. Then enter GOTO
2000 without a line number and press NEW-
LINE.
4) Enter the values in Listing 3. After
8) You are now ready to embark on the
Chase. Press GOTO 50, and the Chase
field will appear.
9) If you want a hyperspace leap, add
the following lines: i
365 IF Y=10 THEN LET C=RND(18)
367 IF Y=10 THEN LET B=RND(8)
However, you must shorten the print
statements to accommodate these lines.
10) For those who want to modify the
program:
USR(16427):
prints the outside fence of the field.
USR(16482):
gives the memory location of the screen.$
USR(16487):
increments the units of memory. "n
Sample Run
By using machine language, the time that each number hit NEWLINE (do not enter ar pi
it takes to print the whole image along the commas). This must be done very care- B fe
with the calculations is less than two seconds. fully. Ü nu
Changes of the pattern during the game 5) Type in Listing 4. Enter GOTO 2000 Bs e£
are POKEd directly into the screen instead without a line number and press NEW- D Dx
of printing the whole pattern again. LINE. i i
The symbols used are: 6) Type in Listing 5. Then enter GOTO de o
+ (in inverse video) = robot 2000 without a line number and press NEW- p o
* (in inverse video) = you LINE. a s
X — fence or mines 7) Delete lines 2000-2010 by typing just E E
gi — fence the number and NEWLINE. re Se: d
O E UMD E OE. 8) Type in with no line numbers: A a
Kenneth Yu, 1145 West 32 Ave., Vancouver, B.C. LET F=100 and NEWLINE OR UM E np.
V6H 2H8, Canada. LET G=0 and NEWLINE
September/October 1982 75
Z= WEST
FREE SOFTWARE!
in our sinclair user
NEWSLETTER
EVERY MONTH YOU
WILL RECEIVE NEW
PROGRAMS, ARTICLES
AND INFORMATION ON
ZX COMPUTERS.
for your sample copy
send 37 to:
Z-WEST
PO BOX 2411
VISTA, CA. 92083:
BARLOG<
SOFTWARE
@EAGLE LANDER: -1K a hae
oon landi ti
ins PLOT IK $2 06
UR
C Graphic routin
eMEAL-A-MORPH -16K
Survival jn cafeterias
eTEXT R-16K
Text editor, printer commands
Send 20¢ for full list
ALL listings explain Prostar
in detail.
Make check to:
BOB LUCAS
. 401 N. GEYER ROAD
KIRKWOOD, MO. 63122
V $39.95 (KIT)
$59.95 (A&T)
ANALOG INTERFACE FOR THE ZX81
Welcome your computer to the “real vond: of analog
signal processing. VOTEM is a o plete package,
sisting of the necessary hardwar ang sowar to en Gable
our com puter to measure Pots
and temperatures.
OTEM also includes circuitry that condi tions the tape
signal for dependable LOADs.
* Software compatible with Timex TMS-1000, Sinclair
ZX81/80-(8K)
* Requires absolutely no modifications to computer
* Measures voltages and temperatures
Probe provided for air and liquid temperature
MU
* Resolution is better than 14 bits (0.00005V or 0.04
degrees C)
e Voltage range of + 1V can be expanded with on-board
resistors
Ow power, requires less than 20mA at +11V
un VPE i a
* Can be powered from computer's supply (cable included)
* Tape signal conditioning circuitry
* Tape signal monitoring capability (audio and visual)
* Manual includes detailed kit assembly and calibration
* Software for calibration and applications fits in 1K RAM
* Instructions for adapting to other Z80 computer systems
* Conipact, 1" by 4" by 3"
Also, static RAM chips, 6116P-3 (2K by 8) with instructions
for or upgrading Sinclair 2 2X81 computer from 1K to 2K. Only
$11 k or money order. Include $3 shipp-
ing and handling.
Down East Computers
P.O. Box 3096
Greenville, NC 27834
76 -
Listing 1.
1 REM 12345678901234567890123
45678901234567890123456789012345
6789012345678901234567890
10 PRINT "YOU HAVE DESTROYED T
HE ENEMY"
20 INPUT AS
"50 FOR D=1 TO 21
-60 LET A(20*E(D)+F(D))>)=0
70 NEXT D
80 IF G=5 THEN GOTO 110
LET K=100
LET G=0
RANDOMISE
LET A=USR(16427)
PRINT "ENERGY-";K,"H.S.";F
FOR D=1 TO 21
LET C=RND(18)
LET B-RND(8)
LET M=20*B+C
IF A(M) THEN GOTO 160
LET A(M)=61
IF D«6 THEN LET A(M)-147
IF D=6 THEN LET A(M)=148
LET E(D)=B
LET F(D)=C
POKE USR(16482)+M+B, A(M)
NEXT D
270 LET B-E(6)
LET C-F(6)
LET M=20*B+C
LET A(M)=0
INPUT Y
IF Y THEN POKE USR(16482)+M
+B,0
330 IF Y=1 OR Y=2 OR Y=3 THEN L
ET B=B-1
340 IF Y=5 OR Y=6 OR Y=7 THEN L
ET B=B+1
350 IF-Ys1 OR Ys8 OR Y=7 THEN- E
ET C=C-1
360 IF Y=3 OR Y=4 OR Y=5 THEN L
ET C=C+1
Listing 2.
2000 FOR X=16427 TO 16506
2001 INPUT A
2002 PRINT A,
2003 POKE X,A
2004 NEXT X
Listing 3.
42,12,64,35,205,74,64,6,8,197,
54,9,35,6,18,54,0,35,16,251,54,
9,35,62,117,60,119,35,193,16,
234,6,20,54,9,35,16,251,62,117,
60,119,35,34,14,64,34,16,64,62,
13,50,37,64,201,42,12,64,35,201,
42,12,64,6,0,14,220,9,126,254,
37,40,02,52,201,54,28,43,24,244
370 LET M=20*B+C
380 IF A(M)=61 THEN PRINT "YOU!
TOUCHED THE FENCE"
390 IF A(M)=147 THEN PRINT "YOU
/BUMPED INTO THE ENEMY"
400 IF A(M)=147 OR A(M)=61 THEN
GOTO 660
410 POKE USR(16482)+M+B,148
420 LET A(M)=148
430 LET E(6)=B
440 LET F(6)=C
450 FOR D=1 TO 5
460 LET M=20*E(D)+F(D)
470 IF A(M)-147 THEN GOTO 610
480 LET A(M)=0
490 POKE USR(16482)+M+E(D) ,0
500 IF E(D)<B THEN LET E(D)=E(
D)+1
510
D)-1
520
D)+1
530
D)-1
540 LET M=20*E(D)+F(D)
550 IF A(M)-61 THEN POKE USR(1
6482)+M+E(D) ,147
560 IF A(M)=148 THEN PRINT "YO
U HAVE BEEN DESTROYED"
570 IF A(M)=0 OR A(M)=148 THEN
#GOTO 610
580 LET K=K+1
590 LET G=G+1
600 LET A=USR(16487)
610 IF A(M)=0 THEN LET A(M)=14
7
IF E(D)>B THEN LET E(D)=E(
IF F(D)<C THEN LET F(D)=F(
IF F(D)>C THEN LET F(D)=F(
IF G=5 THEN GOTO 10
IF A(M)=148 THEN GOTO 660
NEXT D
GOTO 270
IF K>F THEN LET F=K
Listing 4.
DIM E(21)
DIM F(21)
FOR D=1 TO 21
LET E(D)=0
LET F(D)=0 >
NEXT D
Listing 5.
DIM A(200)
FOR B=0 TO 9
FOR C=0 TO 19
LET M=20*B+C
LET A(M)=0
2006 IF B=0 OR B=9 OR C=0 O
R C=19 THEN LET A(M)=61
2008 NEXT C
2010 NEXT B
SYNC Magazine
Space Taxi
Neil Dewhurst
You are the pilot of a space taxi in the
year 2081. You have just picked up a fare
who must catch the next ship to Zeta Chi
LXXXI. Naturally, there is a big tip if you
make it in one piece. You control your
taxi by the 6 and 7 keys to avoid the
buildings and the other traffic (which
appears to be standing still because you
are going so fast). If you crash before
Neil Dewhurst, 2 Chesterbrook, Ribchester, Nr.
Preston PR3 3XT, U.K.
F4 ELE
ead lik
REF
getting to the spaceport, the space odo-
meter will show how many blocks you
passed before the crash.
Type in the program and then SAVE it
before playing. After SAVEing, hit SLOW
and ENTER. Your taxi is immediately
underway. So be prepared to drive with
the 6 and 7 keys.
Graphics note:
Line 60: inverse space.
Line 150: inverse graphic on M.
Line 1010: inverse space.
Line 1030: inverse O. a"
464 nàen
es
CA ELI “u
a e.
a4 o rene e ”
8K ROM
1K RAM
14 LET 5=9
LU =
20 Er Y=2
SB ET x BS
4v CLS
50 GOSUB age
SS ET AT ax “E
39 IF e M ="7?" THEN LET D=-1
390 IF pH aaa '&" THEN LET D=1
15x LET o > +1
ET X=X+1
12D IF xz31 THEN GOTO 30
149 IF vxi T THEN LET Y=1
150 PRINT AT e
TOR PRINT
178 IF PEEK (PEEK i6s9s+256 PEE
K 128938) = hat do THEN GOTO 66
138 INPUT Js
@ RUN
19000 FOR J-O0 TO
1945 FOR Is1 TO S+7NT
1918 PRINT AT l.J. “Be PIER
1015 NEXT I
1928
NEXT J
1925 FOR I21 TO 45
10308 PRINT AT INT (RND#5) +41. Iž:
1835 NEXT I
1040 RETURN
BLACK ACER MASTER Es
lip to ? Players with
erPhions like Double Down.
maie. mit
Pairs. Sue Qut. and LENGTH
more! Don't settle for less. ze ee
FOOTBALL FORECASTER bs Ls
fe a AH, Fo 1 t
MARTA
oP Lit
“rink
Get bhis one GUICEkE as the data
pase iz for thie SSRs zeacon.
Spas COLLEGE oe FRO wees dori
Marea Order Gete rus deliver,
REwViRSI bu Peter
a Plasers, acainzt the Gl.
make it mias itzelf.
nz + oPbional RATED
Possible moves, "RAL"
leiger
list
E 1 td " tnd Ww pa E n d-
Each ¿ETA Proc*urmam is
a certified cassette
2.58 for the
ahi Prac
Fast PE
maf
wero Lor |
ander,
eT
kape with
informative booklet, Catalog
sent with apcep or weite:
EY m i co AF”
o ü E Li; x
TY bip Ez
ud e
September/October 1982
"GREENVILLE ». SC 29689
PREMIUM DATA CASSETTES
*MANUFACTURERS WHOLESALE PRICES*
1 CASSETTE 100-PACK 500-PACK
.54 EA. .45 EA.
C-20 .66 .61 53
C-60 .89 .83 LO
C-90 $1.29 $1.21 $1.14
SOFTWARE PUBLISHERS —LET ACTS AUDIO
PROVIDE YOU WITH ALL YOUR CASSETTE
PRODUCTION REQUIREMENTS.
CUSTOM SOFTWARE DUPLICATION — FOR
SINCLAIR, TRS-80, APPLE, ATARI — GUAR-
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ACTS AUDIO ALSO SELLS HIGH-SPEED
DUPLICATION EQUIPMENT MODIFIED FOR
SOFTWARE DUPLICATION.
ACTS AUDIO, INC.
70 WEST ILLIANA AVE.,
ORLANDO, FL. 32806
(305) 423-0338
77
-< Book Review
The Complete Sinclair ZX81
Basic Course Fred Biechman
The Complete Sinclair ZX81 Basic
Course. Published by Beam Software,
U.K. and Australia. 255 pages; softbound
with two hole punched pages and two
rings. In U.S. available from Softsync for
$35; two program cassettes, $5.
It has been said, “It's not what some-
thing costs that counts; it’s what it’s
WORTH! That certainly seems true in
the case of The Complete Sinclair ZX81
Basic Course. You get 255 pages of 8-1/4'
x 5-1/2* two-hole punched sheets held
together by two rings in a fancy vinyl
cover. Thirty-five dollars for this? It looks
like a real ripoff!
Further inspection does not help. No
author's name is given— just Beam Soft-
ware, with publishers in England and
Australia. Look in the back for an index,
and you will not find one. Look in the
front for a table of contents, and you find
a single page headed “INDEX.
First impressions, however, can be
deceiving.
The course begins with the assumption
that you know practically nothing about
Fred Blechman, 7217 Bernadine Ave., Canoga
Park, CA 91307.
ZX81 VIDEO INVERTER ADDS PROFES-
SIONAL TOUCH.
NO MORE EYE-STRAIN.
DISPLAY SHARP WHITE CHARACTERS
ON SOLID BLACK BACKGROUND TV
SCREEN.
A TOGGLE SWITCH LETS YOU CHOOSE
BETWEEN NORMAL AND REVERSE.
THE SMALL PRINTED CIRCUIT BOARD
FITS INSIDE YOUR ZX81.
ALL FULLY TESTED WITH CONCISE
INSTRUCTIONS.
MONEY BACK GUARANTEE.
AVAILABLE AS KIT £5 / $10
READY BUILT £6.50 / $ 13
PRICES INCLUDE AIRMAIL. SEND £ OR $
CHECK.
D. FRITSCH
6 STANTON ROAD
THELWALL
WARRINGTON
CHESHIRE
WAA 2HS
UK
computers or programming and holds
your hand pretty tightly. If you are a
beginner, you should go through each
example with your ZX81 at your side.
However, later chapters go into depth on
some very valuable material for those
intending to do significant programming
on the ZX81.
Chapter 1 starts with simple pro-
gramming that a beginner really should
be able to follow. This is unlike many so-
called beginner's books. Chapter 2
explains simple flowcharting. Chapters 3
and 4 go into arithmetic operations and
functions in depth with examples to
explain the purpose of various functions
while avoiding mathematical theory.
Chapters 5 and 6 do a great job of
explaining strings and string functions,
including “slicing' and substring handling.
Chapter 7 covers editing with more infor-
mation than the Sinclair manual. How-
ever, it should have gone into more depth
since efficient editing can be a real time-
saver in programming. Chapters 8 and 9
explain loops and conditional statements
well. Chapter 10 covers arrays, both
simple and string. This is a subject of
immense importance in the ZX81 since
READ/DATA are not provided.
SAVE YOUR MEMORY!
AND YOUR MONEY!
Battery backup unit for ZX80/81.
This inexpensive unit lasts for 30
minutes on standard "D" cell bat-
teries, protecting your valuable
programs from glitches and power
failures. Requires at least a 9 volt
power supply (like Sinclair's) and 6
“D” cells (not included).
Only $12.95
VOCAB BUILDER for ZX81 16K 60
words per cassette, for teens and
adults $9.50
Send check or money order to:
CSI COMPANY
132 E. PASCO LANE
COCOA BEACH, FLA 32931
Chapters 11 through 15 cover subrou-
tines, character codes and graphics,
FAST and SLOW operation, screen for-
matting, graphic layout, INKEY$, and
PAUSE.
Chapter 16 describes procedures for
using a cassette recorder to store and
retrieve programs, and Chapter 17 dis-
cusses a programming method known as
"top down programming." Chapter 18 has
an excellent discussion of debugging
programs along with expanded explana-
tions of what the 15 ZX81 errors codes
really mean.
Chapters 19 through 22 get into the
high ground of memory saving tech-
niques, machine code programs, system
variables, and advanced graphics. These
chapters are definitely not for beginners,
but greatly increase the value of this book
for non-beginners. PEEK, POKE, and
USR are illustrated with line renumber
and memory-size machine language pro-
grams cleverly hidden in REMark state-
ments at the beginning of a Basic pro-
gram. The various system pointers are
discussed in sufficient detail to help you
understand the very peculiar goings-on
"under the hood," including the wild
antics of the elastic display file of the 1K
ZX81. For those schooled in a different
memory access, such as the TRS-80, this
will be a real education! These chapters
are just loaded with information either
not available or well-hidden in the Sinclair
Manual.
The three appendices include the stan-
dard 255 character set with all keywords,
a priority listing for program operations,
and several application programs that
implement the techniques described in
the book.
The last 78 pages are a reference
manual of all 64 ZX81 keywords, with a
page or more of explanation devoted to
each. For beginners and those not
acquainted with some of the peculiarities
of Sinclair 8K Basic, these pages are a
treasure that can save a great deal of time
and avoid much frustration, especially in
translating programs from other Basics.
This section alone may be worth the price
of the book.
Two cassettes, containing 18 programs
from the book, are available separately.
They loaded and ran perfectly. This saved
a great deal of keyboard and debugging
time.
If you have any interest in learning to
program your Z X81, especially if you are
new in computing, I would recommend
this course highly. If you are already a
user, you probably do not need it. Instead
you might buy ready-to-go programs and
just enjoy! a
SYNC Magazine
Software Review
ZX81 Chess vs. ZX Chess Il
ExL ap | a
SOFTWARE PROFILE
Name of Package: ZX81 Chess.
ZX Chess II.
T ype: Board Games
- System: Sinclair 8K ROM; 16K RAM
Format: Cassette
- Summary: Two powerful chess
a programs
- Price: ZX81 Chess: £9.50.
. ZX Chess II: £15.00
Manufacturer:
(ZX81 Chess)
» . Micro-Gen
—. 24 Agar Crescent
| . Bracknell, Berkshire, U.K.
— (ZX Chess II)
Artic Computing
396 James Reckitt Ave.
Hull, North Humberside, U. K.
ARE chess is becoming a very
popular hobby for those who cannot find
opponents on their level, and a large
number of “dedicated” machines are
appearing with increasingly greater
strengths. Another area of growing popu-
larity is designing a chess program which
is more powerful (i.e., a better player)
than other chess programs. Two powerful
chess programs are now available for the
16K ZX81: ZX81 CHESS by Micro-Gen
and ZX CHESS II by Artic Computing.
Both programs are supplied on cassette
with detailed instructions. ZX81 CHESS
has six levels of play; ZX CHESS II,
seven. Both games set up a board and use
the standard notation with rows 1 to 8
going up and A to F going left to right.
ZX CHESS II also shows the letters of
the columns and the numbers of the rows
on the screen for quick reference when
entering a move. The 24x24 board of ZX
CHESS IT is somewhat easier to use than
the 16x16 board of ZX81 CHESS. The
pieces are represented as s follows: K
King, Q = Queen, R = Rook, B =
Bishop, N = Knight and {= = Pawn. Black
pieces are shown as black on white and
white pieces as white on black.
Martin Wren-Hilton, 4 Little Poulton Lane,
Poulton-le-Fylde, Blackpool FY6 7ET, U.K.
Martin Wren-Hilton
Entering your move is simple on both
programs. For example, to move a piece
from position E2 to E4 you would enter
E2-E4 on ZX CHESS and E2E4 on ZX
CHESS II.
(Continued on p. 84.)
Figure 1: A Game between
— — ZX81 Chess and ZX Chess I] ___ . —
ZX81 Chess ZX Chess II
Di D2-D4 G&-FE6
ue 61-C3 D?-b3
3 ci-F4a cC&-FS5
@4 Gi-FS E?-EG
25 F4a-GS 68-07
E n2-n4 Fo-bo
BY H2-H4 ES-GE
@S E2-E3 H?-H6
eG GSxFG& DGXF6
10 Fi1-D3 FSxo3
2 C2XD3G FE-FS
ie E1-Gi '2-C6
13 FI-E1 no-ca
id R4-n5 FS-ES
i5 AS-AG 67-B6
io G2-G3 66-65
43 61-562 585-54
18 C3-E2 H6-HS
19 —El-H1 D?-FE&
20 bi-C2e F6-D?
21 B2-B5 c6-cs
22 E2-F4 cCSxDd4
23 Ce-Ee XE
24 E2XES DOXF4
25 ES3SXF4 FO5xD3
26 F4x5B4 D7-C5
27 B4-D2o D3XB3
28 D2-GS5 3G7-G6G
33 . F4-n4 ne-B4
34 A4XAP 54-C2
35 AIi-AS BS5-B4
36 RS-A4 Bd-C5
3? AY-AS C5-C3
33 AS-AY ES-Cd
39 RáxC4 DSXC4
38 FS-ES C2-E1
41 Ge-Gi 'ESXES
42 GS5SXES El-F3
43 Gi-Fi FSXES
44 AP-AS — ES-D?
45 Fi-G2 ¢4-€s3
46 AS-GS 3c3-ca
47 GS5xG6O F?XGE
43 F2-F3 C2-C1
49 G2-F2 Cl-D2
coa F2-Gi1 Db2-E3
Sl Gl-G2 E3-E2
&2 G2-H3 E2XFa3
S53 H3-H2 GS-H?
Sá G3-G4 Fi3xG4
59 H2-H1 G4-HS
5S6 H1i-Gl HSxXH4
SY G1-G2 H4-F4
53 G2-HS F4-GZ5
S39 H3-He9 —HE-Ha
58 H2-H1 Hi-H3
list
YOUR SOFTWARE
now for the February catalog
SELL IT—SHARE IT
You made it to fit your specific
needs and it will meet the needs of
hundreds of other Sinclair users
who will
ORDER FROM YOU AT YOUR
PRICE
software category
[ ] Business Applications
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Brief description (100 characters
max.)
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Available as
[]Cassette$ | (US)
[]sourcelist $ 1 (US)
Name
Address. A d v. er Rua cl
E vo A aS PLUS
State/Prov
ZiD/Postalepüe ci le WA
[ ] Listing(s)
$10: 5£ per listing .00
[ ] Purchase _ copy(s)
Sinclair Software
Sourcebook ($8/4£ ea) .00
C] Check or Money order
[C] Visa or Mastercharge
#
QE V. PRAE ee
Drivers Software Sourcebooks
PO Box 1048 Port Hardy
British Columbia, Canada,
VON-2PO
4K ROM; 2K RAM ; 16K RAM
You are trapped in the dreaded “House
of Horrors.” Naturally it is filled with
monsters, mummies, skeletons, and
strange creatures. Secret passages and
mysterious rooms confront you with
danger and yet offer the only way out.
Your goal is to escape from the house
alive.
As you move through the rooms, you
find various items to help you survive,
but you do not know exactly what they
will be. So you must depend upon your
wits, memory, and logic to escape.
The full House of Horrors program
requires somewhat over 2K RAM. As a
result, it is split into two sections. Type in
Listing 1 and SAVE it. Do not kill the
program, but enter the changes in Listing
2 and SAVE the program again. Now
LOAD Listing 1 from your tape and RUN
it. This part of House of Horrors fits into
2K RAM. It can be played as a game in
itself for those who have only 2K RAM,
and it is a segment of the game for those
who have enough memory for the lower
level. When the prompt “READY
CASSETTE” appears on the screen, you
have reached the end of the game if you
have only 2K RAM.
However, if you have more RAM, set
the tape at the beginning of Listing 2, hit
NEWLINE, and press the play button on
your tape recorder. When the LOADing
is finished, press RUN and NEWLINE to
continue your efforts to escape.
While the program was written for the
4K ROM, it should not be difficult to
translate to 8K ROM. This will require
Douglas Duchene, Lot 59 Gatewood, Greenwood,
SC 29646.
80
House of Horrors
Douglas Duchene
changing the PEEK addresses, the array
subscripts, some of the character codes,
logical expressions, and the TL$ function,
10 REM 1728630UTSIDE, KITCHEN, E
AR. LIVING ROOM, DINING ROOM, FIT, L
LIBRARY, BEDROOM, HALL, ENTFE, SCROLL
s WINE, HEY, BOOK, ROFE, 60 RUNWALCLI
JUMGETTARDROLEALOOOFEREADRIINVSH
^
20 DIME)
SOS FOR dao. T0.5
40 LET 1(J)=PEEK (J+16427)—-29
uo NEXT J
60 PRINT
ZO PRINT
80 LET R=0
90 PRINT "YOU ARE *;
100 IF R THEN FRINT "AT THE A
110 LET X=7
120 LET G=R
122 LET P=16432
124 GO SUB 9000
130 FRINT
140 FRINT "ITEMS HERE: "
145 LET F=0
150 FOR @=0 TO 5
160 LET F-16501
"HOUSE GF HORRORS"
163 LET Z=k
170 LET X=5
175 IF F=1
180 IF 1(0)=Z
190 IF 1(0)=Z
200 NEXT Q
210 PRINT ";"
220 INFUT R$
230 CLS
240 LET P=16534
250 FOR J=1 TO 15
260 IF CODE(RS)=PEEK(P) AND COD
E (TLS CR$0 ) -PEEE (F+1) AND CODE (TL
$CTL$(RS$))) -PEEK(CF--2) THEN GO TO
310
270 LET P=F+3
280 NEXT J
290 PRINT "I
THEN LET
THEN GO SUB 9000
THEN PRINT
Z=0
DONT UNDERSTAND"
Listing 1. The House of Horrors (Upper Level).
e.g., 310 would become LET R$=R$(2
TO ).
For users with enough memory the
game can be made more complex by
increasing the number of rooms and items
available.
200 GO TO 210
210 LET Re=TLhe (RS)
220 IF R$="" OR CODE (R$)=0 THEN
DO r0 3550
220 60. TO 310
S30 LET OR$=TLS (R$)
240 GO TO (J+5) *100
400 LET Z=1
410 IF Re="N" OR R$="S" THEN LE
T Z-3
420 IF R$="4" QR R$-z'"N" THEN LE
T ZsZX*-1
430 IF R$="N" OR R$="S" OR R$"
E" OR R$-"W" THEN GO TO 460
440 PRINT "N:S:E:u"
4950 GO TO 210
460 IF R+Z<9 AND R+Z>0O THEN GO
TO 4390
470 FRINT
GG "R$
480.60. TO 210
490 LET R=R+Z
493 GO TO 90
800 60 TO 400
900 GO SUE 1900
903 IF NOT I¢J)=R THEN GO TO 19
70
910 LET. TCJ) »O
920 -FRINT "Ok."
430 GOTO 210
1000 GO TO 900
1100 GO SUB 1900
1110 IF NOT 1(J)=0 THEN GO TO 21
O
ELIS LET T QlYsH
1120 GO TO 920
1200 GO TO 1100
1500 GO TO 90
TAOD PRINT: CI-CANTA
1410 GO TO 210
1300 IF R="SCROLL"
THEN 60 TO 1510
"THERE IS NO WAY TO G
OR R$="BOOK"
SYNC Magazine
C
| The Si
Imagine building your own computer
for only $79.95!
That's exactly what you can do with
the ZX81 kit. It comes with all the parts
you need and complete diagrams and in-
structions for putting it together. All you
have to supply is soldering iron, solder,
and a screwdriver. Plus, of course, a little
bit of work.
But you get a lot more than several
hours of kit-building fun. You also get a
surprisingly powerful personal computer.
The ZX81 hooks up to any TV for a 32-
character by 24-line display (we provide
the connecting cables). You can also use a
standard cassette recorder to store your
programs (again, we provide the cables).
Most important, you get a BASIC pro-
gramming language that's powerful
enough to challenge and interest the
most experienced programmers. The
ZX81 can handle multidimensional string
and numerical arrays. It has full mathe-
matical functions accurate to eight deci-
mal places. Single-key entry for every
command. Syntax error detection, de-
bugging codes, and easy editing. Plus
features that are ideal for creating games,
such as 20 graphic symbols, continuous
2 LS an
nclair
"e
P.
hu dt
dis
display, and random number generator.
The ZX81 can be expanded too. You
can increase the memory from 1K to 16K
with our Memory Module for $49.95.
And you get a comprehensive manual
that completely documents the capabili-
ties of the ZX81, and teaches program-
ming from the ground up.
In short, you get all the features that
have made the Sinclair ZX81 the fastest
selling personal computer in the world.
And you get the satisfaction and fun of
building it yourself.
A few years ago, this kind of computer
power was simply unavailable to the
individual. Even today, most personal
computers are too expensive to buy for
personal use.
But the ZX81 kit can be yours for only
$79.95. Take advantage of this unique
offer today. To order, send the coupon
along with a check or money order. Or for
faster delivery, call our toll-free number
and use your MasterCard or VISA.
To order call toll free: 800-543-3000.
Ask for operator 4509. In Ohio call: 800-
582-1364; in Canada call: 513-729-4300.
Ask for operator 4509. Phones open
24 hours a day, 7 days a week. Have your
onsen
wee id.
ag x
i E.
ZX8] personal compu
sS
ter kit
MasterCard or VISA ready.
These numbers are for orders only. If
you just want information, please write:
Sinclair Research Ltd., 2 Sinclair Plaza,
Nashua, NH 03061.
MAIL TO: Sinclair Research Ltd.,
One Sinclair Plaza, Nashua, NH 03061.
PRICE* QTY. AMOUNT
| 4D cone |
09SYOK
ZX81 Kit
16K Memory
Module
| Shipping and
Handling
*U S. dollars
| Name |
ee EM UM IC C c
Sinclair technology is also available in Timex/Sinclair
computers under a license from Sinclair Research Ltd.
Sinclair”
i505 60 TD
1510
HEN FRINT
1340 PRINT
GO DO TO ZLO
15
1600 IF
1610 IF R$="WINE"
i)
1620 PRINT
1400
IF R$="SCROLL "
FIT"
1520 IF R$-"BOOE" AND 1(4)=0 THE
N PRINT "IT SAYS MAGIC WORD (SHA
ZAM) "
1530 IF (R$="SCROLL" AND 1(1)=0)
OR (R$="BOOK" AND I(4)-0) THEN
60 TO 210
"YOU DONT HAVE IT"
IC2) 50 THEM GO TO 1540
"YOU CANT DRINE "sR
15850 BO.TÜU 210
1700 FRINT
"YOU ARE CARRYING: "
IZiQ LEID F-1
1720 490. TO- 1560
1300 PRINT "POOF YOU AFFEAR IM T
EME ty
STO “FRING, READY: CASSETTES"
1820 INPUT R$
1830 LOAD
1900 LET P=16502
1910 FOR J=0 TO 35
1920 IF CODE (R$)=FEEF(F) AND COD
E (TL (RS) ) =PEEK (F+1)
1930 LET P=F+1
1940
IF NUT PEER CP) S216 THEN GO
FO LSO
1950 LET .P=P+1
T9600. MEXT J
"THE RIGHT STUFF"
ZX-81/TIMEX SINCLAIR 1000 16K
GAMES ON QUALITY CASSETTES
"BAC-TRAC"
A "PACMAN" STYLE PACKAGE OF
FUN. 36 GAME VARIATIONS.
"FLIPS"
A TWO-DIMENSIONAL VERSION OF
"RUBIC'S CUBE." FULL SCREEN
WITH 99 LEVELS.
"ARMEGON"
DEFEND YOUR FORTRESS
AGAINST THE INVADING ZARDAX.
10 LEVELS OF PLAY.
“SUB SEARCH"
LOB DEPTH CHARGES AT THE
RELENTLESSLY ADVANCING
SUBMARINES. MULTI LEVELS OF
PLAY.
"BREAK-OUT"
SINCLAIR VERSION OF THIS
TRADITIONAL FAVORITE. MULTI
LEVELS OF PLAY.
ONLY $6. FOR ANY CASSETTE
WRITE:
THE LAMB'S SOFTWARE
1469 AAL BORG WAY
SOLVANG, CA. 93463
AND 1(1)=0 T
"UIDI SAYS ESCAPE: BY THE
THEN 50 TU. 200
THEN RETURN
1970 FRINT HERE
1980 GO TO
2000 PRINT
¿010 PRINT
20/30. 3TUP
9000 FOR J=0 TO X
3010 IF J=Q THEN GO TO 9050
"I SEE NO "sR$;"
210
"IT WAS FOISON"
"YOU ARE DEAD"
9020 LET F=P+1
9020 IF NOT PEEK(F)=216 THEN GO
TO 9020
9040 NEXT J
9050 LET P=P+1
9060 IF PEEK (P)=216 THEN RETURN
9070 PRINT CHRS (FEEK (FD);
9080 GO TO 9050
Listing 2. The House of Horrors (Lower Level Extension).
10: REM 257637 ,FTT PASSAGE, CRYF
T, MAZE, TUNNEL., EMPTY ROOM, TREASUR
E ROOM, LAVA FIT, SWORD, KEY, CHEST,
DOOR, MUMMY, SEELETON, GG RUNWALCL I
JUMGETTARDROLEALODOPEERTLXXX INVXX
X
60 PRINT
CONE"
GO LET R=1
$0 IF R=o THEN GO TO 2000
PLS PRING YOU. ARES":
110 LET X-8
12:2 LET Pz16432
160 LET P=16497
240 LET F-16534
A2 IF NOT J=12 AND
(43:50) OR (I(5055 AND R=7))
G0 TOU.32520
220 PRINT "MONSTER WONT LET ME"
00:60: TD 216
708 IF.J22 THEN? GO-TO" 1120
1150 PRINT "ARE YOU CRAZY
"ALL YOUR ITEMS ARE G
pour Aur)
((R=3 AND I
THEN
RUBIC!S MASTER
FEATURES:
Use as Normal Cube
Enter User!s Cube
Scrambles Cube
***Solves Cube***
Save Current Cube
For ZX90;8K ROM, ZX81
16K RAM Required
On Tape with
Instructions
JEU INTELLIGENT
PeO. Box 71
Glasgow,VA 24555
Price $15 Add $2 for
lorders outside U.S.
If You Can't Solve It
EC CAN.
1140 GO TO 210
1470 IF R$="DOOR"
N GO TO 3000
1480 IF R$-"DOOR" OR R$-"CHEST"
AND 1(1):30 THEN FRINT "I CANT"
1490 IF R$-"CHEST'" AND 1(1)=0 TH
EM RENT STTS EMPTY:
1495 60 TO 210
1500 IF Ré="ME" THEN GO TO 2010
1505 IF -1.00)>0 THEN GO 71051380
1310 IF R=3 AND R$="MUMMY" THEN
LET TCH) =]
AND 1(1)=0 THE
130 IF R=7 AND R$="SEELETON" TH
EN Le Tut ha) ad
15.30 OU TO. 210
1380 FRINT "WITH WHAT MY HANDS?"
1585 PRINT "IT ATTACKED YOU"
1590 60 TO 2010
1900 LET F-16498
2000 FRINT "YOU FELL IN"
3000 FRINT "YOU HAVE ESCAFED"
2010 STOF
SHELF CONSCIOUS?
Now you can organize your copies of
SYNC
Now your magazines can be a handsome addition to
your decor, well organized, and easy to find, thanks to
these durable library-quality cases or binders
They're made of luxury-look leatherette over high-
quality binder board. And both styles are custom-de-
signed for this or any other magazine
you save, with size, color and imprint
selected by the publisher. FREE
transfer foil included for marking dates
and volumes.
Magazine binders
hold a year's issues on individual snap-in
rods, combining them into one volume.
$7.95 each; 3 for $22.50; 6 for $42.95. Mixed
titles OK for quantity prices.
Open-back cases
store your issues for individual
reference. $6.95 each; 3 for
$19.75; 6 for $37.50. Mixed
titles OK for quantity prices.
For faster service,
CALL TOLL-FREE 24 HOURS:
800-345-8112
(In PA only: 800-662-2444.)
P.O. Box 5120, Philadelphia, PA 19141 |
Please send: [_] Cases [ ] Binders
TITLE QUANTITY |
Sync APD EEA
Other: —— — |
[ ] PAYMENT ENCLOSED $ * Add $1.00
per order for postage and handling. Outside USA add
$2.50 per unit ordered; send US funds only.
|
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Print Nate oL M E EL ee |
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(A *Residents of PA add 6% sales tax. J
SYNC Magazine
exe |
FOR THE TIMEX-SINCLAIR 1000, ZX81, (AND ZX80 WITH 8K ROM)!
THE ZX81 HOME COMPUTER PACKAGE
ETCH-A-SCREEN
Easily paint pictures anywhere
within the top 17 rows. A moving
cursor travels up, down, right, left,
even diagonally, leaving behind
text, graphics, and inverse charac-
ters. Keys REPEAT while held
down. Your drawing can be stored
on tape... and immediately ap-
pears when reloaded. Perfect for
designing screen logos, or just
doodling on the screen
BILLBOARD
CHECKBOOK BALANCER
Keep a running tabulation of your
bank account. CHECKBOOK BA-
LANCER displays your current
checkbook balance, (up to
$59,999.99), your latest account
balance, and a list of up to 22
transactions which haven't
cleared the bank. A plastic-coated
keyboard overlay defines ENTER,
VOID, CLEAR, and DISPLAY keys.
And a SAVE key stores the up-
dated program on tape.
Use BILLBOARD for messages,
displays, and exhibits. Type in a
message of up to 250 letters, and
press ENTER. A row of giant let-
ters moves smoothly across the
screen, repeating your message
until you press NEW and enter a
new message. Or, press SAVE and
store the message on tape. When
reloaded, the message begins au-
tomatically.
COMPOSER
A keyboard overlay transforms your computer into a four-octave musical instrument which broadcasts music as
the keyboard is played. Listen to the music through a radio placed beside the computer, or through an amplifier and
speakers. Or record the music directly onto tape. The last 175 notes played are stored in memory, and can be played
back or edited. EDIT keys let you change notes and single-step forward or backward through the piece. SPECIAL
EFFECTS keys are used to create unusual sound effects like laser blasts and arcade noises.
The complete ZX81 HOME COMPUTER PACKAGE, including cassette
of four programs, manual, guide cards, screen display sheet, musical
score sheet, and TWO FULL-COLOR KEYBOARD OVERLAYS, is just
$9.95. Shipping and handling included! $9.95
From: LAMO-LEM LABORATORIES, CODE209, BOX 2382, LA JOLLA, CA 92038
For the ZX81, TIMEX-SINCLAIR 1000, and 8K ROM ZX80 or MicroAce
NAME
ADDRESS
CITY
STATE/ZIP
Our catalog, with screen display
and coding sheets, is free!
SINWARE announces
Z EXTRA
An original new graphics control pro-
gram for the ZX81 or TS1000.
Z EXTRA gives you fast machine-lang-
uage control of all the standard ZX graph-
ics and display features direct from the
keyboard. No programming required to
create, save, print or display screen after
screen of text and graphics. Z EXTRA
features blinking cursors, repeating keys,
four write directions, eight plot direc-
tions, 4x 4 and 8x8 character sizes, in-
sert, delete and many other convenient
functions for creating screen displays.
Easy menu selection of single-stroke —
commands to save multiple screens to
tape or in print, display them in se-
quence or in scrolls, revise, reorder or
search for data entries.
Z EXTRA turns your: ZX81 into an elec-
tronic notebook with a stretch of screen
space as long as your memory (RAM).
Use it for free-form lists, formatted data
files, data displays, moving billboards, etc.
Z EXTRA requires a ZX81 or TS1000
with at least 16K of RAM and is especially
useful with 64K. Just $19.95 on cassette.
HOT Z is an easy-to-use disassembler/-
editor and machine-language monitor
that gives your ZX computer the speed
and response of a Z80 hot rod. Special
entry modes take the tedium out of hex
code entry. Extensive debugging facilities
let you track down errors fast. Cursor-
driven editing functions simplify correc-
tions and revisions. Labels let you create
annotated listings of RAM or ROM con-
tents that stay understandable.
HOT Z now runs your ZX printer as well
as the cassette for full documentation of
your machne-code routines.
HOT Z's detailed instructions are ideal
for the beginner or part-timer.
HOT Z is available for ZX80 or 81, in ver-
sions for 16K or 32K +. Please specify.
Only $19.95 on cassette.
SINWARE
BOX 323, DIXON, NM 87527
84
ZX Chess vs. ZX Chess ll, Continued...
Both games make use of the En Passant
privilege and display the move as PXPEP
(pawn exchange pawn, En Passant).
Castling is shown as 0-0 or 0-0-0 depend-
ing on the side. If you want to castle, you
must enter the king’s move. You cannot
castle out of check, and both programs
stop and report invalid moves.
Both allow you to change sides, adjust '
the level of play, and alter some of the
pieces half way through the game.
There are some differences. ZX
CHESS II allows you to save the present
board set-up on cassette, to COPY the
screen onto the printer, and to print all
the moves that have taken place in that
game on the printer. On the higher levels
you can even ask it to recommend your
next move.
As a test to see which was the better
chess player, I decided to pit them against
each other. I chose level two on both. On
this level ZX81 CHESS takes about a
minute to decide its move while ZX
CHESS II takes about forty seconds. A
toss of a coin decided that ZX81 CHESS
should go first. Chess enthusiasts will
enjoy analyzing the match move by move.
- The final result was that ZX CHESS II
won convincingly, with a Queen, a Rook,
a Knight and two Pawn advantage! The
final position of the pieces is shown in
Figure 1.
Both games have levels for all players
from beginner to postal chess. ZX CHESS
IT is clearly a better player and has more
features than ZX61 CHESS, but it does
cost £5-00 more. If you have a QS Char-
acter Board, there is a modified version
of ZX CHESS II which shows real full-
size pieces graphically, and very impres-
sive it is, too.
BACK ISSUES OF
SUNCE
Add to your Sync collection today, while
copies are still available. The more com-
plete your library of back issues, the more
authoritative and useful it will be to you.
The earliest available issue is Jan-
uary/February 1981. Order any issues
you wish, being sure to specify the month
and year for each. If a particular issue is
out of stock, your payment will be re-
funded promptly.
Back issues of Sync are priced at
$4.00 each, postpaid. Outside the U.S.A.,
>. us a
de HUM 39 E. Hanover Ave., Morris Plains, NJ 07950 i
Please send volumes of Sync listed below:
PAYMENT ENCLOSED $
(NJ residents add 5% sales tax. E
Mrs
Addres
(please print full name) |
City.
(LISTINGS)
xx Just"
SACK MAN
Travel
through
the maze
and pick ==
up points.But watch
out for the ghosts!
NAVAL COMMAND
Seek and
destroy
the enemy ships.
$3.00 each
Only $5.00
SOFTBEAR for bo th!
1455 Canora,Mt Royal
Qué, Canada. H3P 2J7
SYNC Magazine
A Mouthful for Every Occasion
You can call up sensational headlines,
forceful commands, whimsical state-
ments, ageless wisdom, and irrelevant
nonsense all at the push of a key on your
Sinclair computer with the Mouthful
program.
What the Program Does
Mouthful is a simple text manipulation
program based on the old game of draw-
ing words randomly from a list of assorted
words. Strung together, the words make
up an unpredictable and often hilarious
phrase or saying.
By using the Sinclair computer in a
unique way, Mouthful plays this old game
in a new way. The program chooses a
word from each of the three word lists
(see Tables 1, 2, and 3) and prints the
resulting phrase on your TV screen. You
can generate new phrases as often as you
please by pressing NEWLINE.
Don R. Day, 980 West McFie. Las Cruces, NM
88001.
How to Use the Program
The program for Mouthful is in Listing
1. Type it into the computer carefully.
To begin the operation of the program,
type GO TO 20 and hit NEWLINE. If the
program is running properly, a string
10 GO TO 199
20 DIM AC 159)
30 INPUT AS
40 FOR N= TO 149
50 LET A(N)=CODE(AS)
60 LET AS=TLS(AS)
70 NEXT N
100 CLS
110 PRINT "PRESS N/L TO GENERAT
E PHRASE"
120 INPUT AS
130 PRINT
140 PRINT
150 PRINT
160 PRINT
170 LET N=P
180 GO SUB 328
190 PRINT "y";
4K ROM; 1K RAM
8K ROM; 2K RAM
Don R. Day
prompt (“[L)”) will appear in the upper left
corner of the screen.
Now comes the big decision: What list
will produce the phrase you want? Select
Table 1 for oddball headlines, Table 2 for
zany slogans, Table 3 for high-sounding
Listing 1. Mouthful (4K ROM).
200 LET N=]
210 GO SUB 30
220 PRINT "és
230 LET N=2
240 GO SUB 300
250 PRINT
260 PRINT ,"AGAIN? (Y/N)"
270 INPUT AS
280 IF NOT AS="N" THEN GO TO 18
290 STOP
300 LET I=RND(4)-1
310 FOR M=@ TO 9
320 PRINT CHRS(A((N*4Q+1* 10) +M)
330 NEXT M
340 RETURN
INCREASE YOUR
2X81 PROGRAMS
WITH INFINITY
4 K or more
BOUNCY Entrapped by the mad scientist, Count Von
Der Bouncy, it is up to you to fight off his bizarre
creations known as snogel balls and try to regain
your freedom.
$7.95*
ZX81 OWNERS
SPECIALISED PRODUCTS
MODULAR EASY TO USE
FOR HOME/INDUSTRY &
EDUCATION
TE10 INPUT/ OUTPUT PORT — Easy to use. Fits between ZX & RAM
PACK/PRINTER (if required). No skill required to connect. Can be used for
NIGHT DRIVER Test your driving skills on a desert
road. Through difficult turns and blinding curves,
find out how good you really are.
$7.95*
CASINO/STOCKMARKET Now you can play the slot
machines, keno, roulette, blackjack, and more right
in your own living room/then see how well you can
deal in the stock market. Be a millionaire in one night.
$9.95*
MISSILE STRIKE Defend against enemy missiles &
satellites seeking to destroy innocent cities. You are the
commander of a land-based missile defence center.
The fate of the world lies in your hands.
$7.95*
*(All orders should include $1 for postage and handling. Out
of the U.S., include $2 for postage and handling.)
California residents, please add 612% sales tax.
Infinity Research Development
845 Via de la Paz, Suite A120
Los Angeles, Ca. 90272
such things as:— motor control; sound/music generators, connection to
printers/floppy discs/light pens/other computers, temperature monitoring,
square wave generating, control of rotating aerials, even train sets etc. Port has
16 programmable 1/0 lines and may be used without any electronics knowledge
to connect other add-ons. Motherboard required ONLY when two or more add-
ons are used at any one time.
FULLY ASSEMBLED $29.50
KIT (WITHOUT CASE) $24.50
TE12 4 CHANNEL RELAY BOX — To suit Port Contact rating: — 240v
AC/1,5A — 24V DC or 110V AC/3A. L, to 4 units i.e. 16 relays can be
operated $24.50
TE15 8WAY TRANSISTOR DRIVER — $16.50
TE17 8WAY SWITCH UNIT (EDUCATIONAL) — $21.50
TE18 8WAY INDICATOR UNIT (EDUCATIONAL) — $21.50
TE20 JOYSTICK & FREE GAME — (2 Joysticks may be connected via
Motherborsd.) $21.50
as
TE30 MOTHERBOARD — Allows multiples combinations of add-ons — up
to 16 1/0 lines may be used — $26.50
NOTE: TE 12/15/18 Require 9V. 300mMA
Calculator Type Power Supply
23 + 23 WAY ZX Edge Con $5.00
16 WAY SINGLE SIDED EDGE CON $3.50 EXTENDED PIO NOTES $2.50
PRICES INCLUDE POSTAGE
Receipts always provided: — Delivery normally ex-stock. ADD
Full instructions and examples with all products.
Send for catalog $1.00. Mastercharge/Visa accepted.
SEND S.A.E. FOR CATALOGUE. TELEPHONE ORDERS
ACCEPTED.
DISTRIBUTOR INQUIRIES INVITED
THURNALL (ELECTRONICS) ENG.
DEPT Y, 95 LIVERPOOL ROAD. EN |
| CADISHEAD, MANCHESTER M30 5BG ^]
TEL: 061-775 4461 (24 hour)
J—-
utterances known as aphorisms (e.g.,
Necessity is the mother of invention).
Type in the list you have selected. Be
careful to observe the spaces needed to
pad the words into a ten character field.
Press NEWLINE after the last word. This
stores the words in a single array with
proper spacing for random selection. Note
that using Table 3 requires some program
changes before you type in the list. The
screen will go blank for a moment as the
Table 1. Wacky Headlines.
it COMPUTER}
BANK# CLERK
GOVERNMENT
## COMMITTEE
PROSECUTOR
GENERATES#
NABBED#FOR
ELIMINATES
RECOMMENDS
f? CONDEMNS#
HEADLINES#
EXTORTION#
EFFICIENCY
MODERATION
PRISONERS#
ZX80 does its prestidigitation.
The prompt in line 110 will appear and
all you need to do is follow the prompts.
You can make up your own lists for the
Mouthful program. The list must have
exactly 15 words. No word can be longer
than 10 letters, and, if the word is shorter,
add spaces to fill out to 10 characters.
After you SAVE a program, use GO
TO 100 and NEWLINE to begin exe-
cution of the program. Do not use RUN
Table 2. “Yes, sir!” Slogans.
# # CONSUME#
OBLITERATE
# ADVERTISE
# it REWARD# #
## # WELCOME#
HEALTHFUL#
##MENAC ING#
GANGRENOUS
## LAVENDER#
HONORABLE#
VEGETABLES
INTRUDERS#
HORSEFLESH
BEHAV LOR##
#VISITORS#
and NEWLINE or you will lose your list.
The program can be changed to use
longer lists if you have more memory.
Lists of 30 words or even more can be
entered if array A (line 20) is made larger
and the limit of I (line 300) is increased.
Table 3. Words of Wisdom.
For Table 3 change Listing 1 as
follows:
190 PRINT “FIS THE”;
220 PRINT “#OF#” —
# # BEAUTY}
# # AVARICE#
# NECESSITY
# #HONESTY#
# ## COURAGE#
## SCOURGE#
INSTIGATOR
i # REWARD# #
# BLESS ING?
f LOATH ING#
INVENT ION#
HUMAN ITY##
it # APATHY ##
DEDICATION
# AMBIT ION#
OR RI
GET SMART!
Use Smartware software! We specialize in providing software for 'full-blown'
Now
available in
the United States,
Britains’ best-selling |
stylish yet practical plinth which will angle your TV to
reduce eyestrain, conceal the leads and power supply,
and if you have the 16K RAM it will hold it steady to
reduce crashes. Moulded in tough black ABS complete
with a ready-wired on/off switch. Looks really great !
Please order from our U.S. Agent-Jim Griner P.O. Box 1 Princeville, ILL 61559.
Manufactured By Peter Furiong, Products Unit 5, South Coast Road Industrial Estate.
Peace Haven, Sussex, England Tel: (07914) 81637
86
ZX81 workstation isa
Timex / Sinclair personal computers, Our programs can help you realize the
full potential of your machine, for both entertainment and applications,
NEW RELEASES:
1l. James Bond Adventure #1 - A unique adventure game, in which you must
help ‘Agent 007' make the right decisions to complete his mission, Of
course, you will travel to exotic places, fight against overwhelming
odds, and hopefully save the world.
2, ZX Yahtzee - The classic dice game of strategy and luck, played on a
computer, For one to four players.
3. Wharri - Based on an ancient African game that was played with beans
and bowls. Now you will need concentration and cunning to outwit the
computer.
4. Mailing List / Phone Directory - Store the address and/or telephone
mumber for up to 100 people. Search for entries in a variety of ways.
STANDARD FEATURES:
1. All programs will run on Sinclair ZX81 and Timex 1000 computers with
16K of RAM.
2. Software is shipped on certified error-free data cassettes, with each
program recorded twice on the cassette (just in case one copy gets
accidentally erased).
3. Instructions are supplied as part of each program, rather than on
separate papers which tend to get misplaced.
4. Each program is available on cassette, or in listing form (if you
really enjoy typing).
TO ORDER:
Send a check for $9.95 for each cassette, or $4.95 for each listing, to:
Smartware, P.O, Box 1491, Melbourne, Florida 32935
SYNC Magazine
How the Program Works
When you press NEWLINE after typing
in the list, Mouthful converts the char-
acters into code equivalents which are
stored in array A. The trick to breaking
this array into three separate lists lies in
manipulating the index variable N. This is
done by using a multiplier to force N to
“see” only that part of the array you want
it to. On the first call for a word, the loop
index N is set to 0, and a random number
is assigned to I. Thus, if I is 3, then the
word chosen begins at 0*40 plus 3*10, or
at A(30). On the second call for a word, N
is set to 1 and I is randomly reassigned.
Thus, if I is 5, then the word begins at
1*40 plus 5*10, or at A(90). A third call
prints out a random third word by the
same technique, and the phrase is
finished.
Notes
The following line notes point out some
of the program features.
20-70: Load the word lists into the
program as a single variable, A$.
100: Starts main portion of program;
return point from line 280.
130-160: Help format display.
180, 210, 240: Calls for the random
words.
290: End of main portion.
300: Begins subroutine for word
selection and printing.
340: Return to main program.
8K ROM Changes
Listing 2 gives the translation for the
8K ROM.
The 8K program can also be made to
run continuously by deleting lines 110 to
290 in Listing 2 and substituting lines 110
to 290 in Listing 3.
The 8K ROM version requires over 1K
RAM to run as shown; however, the
continuously running version can be
squeezed into 1K RAM by shortening
array A to about 90 elements and adjust-
ing line 320. Short words can be used to
maintain the variety of phrasing. =
PRESS ENTER TO GENERATE PHRASE
BANK CLERK ELIMINATES HEADLINES
AGRINT (YN)
S0 sa
Set this program up and have it running
at your next party. Your popularity (or
perhaps even your notoriety) will never
be the same again!
Listing 2. 8K ROM.
zCODE R$
e PRI
ATE PHRASE"
1209 INPUT
T
260 PRINT TAB 5; “AGAIN? Y/N)“
270 INPUT As
230 ae NOT AS="N" THEN GOTO 1008
p
300 LET I-INT (RND#4}3 +1
310 FOR ze TO 9
320 PRINT CHR$ (if tIiNE:4O-IEX10) +h
339 NEXT M
340 RETURN
Listing 3. Lines for 8K ROM
Continuous Running.
290 GOTO 100
| BBU—2 "ERIN,
A QOL OR RODEO LOMO HOC NTRS
Tactile Feedback Over lay
Por: a 80/81, Timex 1000, or Microace
* TOUCH TYPING POSSIBLE
** STOP MISSED KEYS
** SPEED ENTERING PROGRAMS
With our easy i install keyboard overlay
3.95
ZX 81 Four Original 16k Programs
On & quality computer cassette
MATH TUTOR
dition Subtraction Multiplication and
Division. With five levels of achievement
in each. From an introductory level to
negative numbers and decimals.Menu driven.
TYPING SKILLS
A fun and competitive skill improver.
You set the speed in words per minute
then try to keep up with the computer.
2 e with our tactile feedback overlay!
Can you guide your missiles to intercept
these horrible swooping creatures, while
dodging what they drop? A ghastly end is
in store if you are hit.
ASTRO SMAS
Pilot your ship through the asteroid belt
to find and destroy as many of the
oppositions lurking ships as you can
before your force shields give out.
Careful though, if you hit the wrong part
of their ship you blow up. Save the best
score and try to better it next time.
$ 12.50 DUTY FREE From:
Site V, RR Y, Nanaimo,
P. Hargrave,
B.C. Canada
V9R5X9,
ZX TELEPHONE BOOK
e Holds 720 names plus easy ADD/CHANGE/
DELETE functions!
e Extensive "learner friendly" documentation even
shows you how to add multi-access capabilities!
e Get this high performance 8K/16K listing at BIG
SAVINGS:
e Only $4.95 from:
THOMAS B. WOODS
BOX 64
JEFFERSON, N.H. 03583
STAR VENTURE
GAME:
Seek out and destroy enemy
vessels to move up in Star Fleet
ranks.
Program listing
Cassette
$1.00 shipping
OTHER PROGRAMS
AVAILABLE
Games, Accounting, and
Microwave Cooking Chart for
8K/16K, ZX80/ZX81.
DSBC
P.O. BOX 1251
DOLAN SPRINGS,
ARIZONA 86441
edieval antasy
A graphically animated adventure game
> in a small world. Fight monsters
gain power, wealth and magic items.
de Ti apa 1000 with 16K or more of RAM.
The price is $9.95 o p: shipping 4 handling.
Daw Software, 78 Aberdeen Pl., Clayton, MO 63105
88
harcgware tings
Some MicroAce
Hardware Peculiarities
Irving Chaiet
Problem 1: Keyboard Entry
If your MicroAce will not accept key-
board entries or will accept some, but not
all, the most likely hardware problem is a
defective IC U11, a 74LS365.
The solution is to replace it. You must
know that the replacement part (either a
new 74LS365 original part or a substitute
74LS367) is a good working part, i.e., it
has been tried in a working MicroAce
and it works perfectly. I had ordered six
74LS365s from one source, and none
worked properly. Even the replacements
did not work. Then I ordered from
Jameco three types (3-SN74365N, 3-
74LS365, and 3-DM9085N which are
equivalent made by National Semicon-
ductor). All of these worked fine.
Sometimes IC19, a 74LS04, would not
allow the computer to accept the shift
key entries of + ( - ) >. Changing the
IC19, the 74LS04, seemed to correct the
problem.
Problem 2: Cursor Flicker
If your K cursor flickers or if the LS
display flickers when the LET command
is keyed in, the problem may be a defec-
tive IC U24; a 74LS74. The C12, a 47PF
capacitor, could also be at fault. A good
substitute for the latter is a 100PF capac-
itor.
Spare Chips
Since the LS series of chips used in the
MicroAce is not expensive, I suggest
having a spare set of known good chips
on hand. Though you might never have
to use them, the assurance of being able
to plug in a known good chip balances off
| the possible frustration of time delay and
expense in sending the instrument out for
repair.
Here is a list of the chips to have on
hand: 1-74LS00, 1-74LS04, 1-74LS05, 1-
74LS 10, 1-74LS32, 1-74LS74, 1-74LS86, 1-
74LS93, 1-74LS157, 1-74LS 165, 2-74LS365
or 74LS367 or plain 74365, 1-74LS373.
Note: be very careful to plug in the
chips properly. Pin 1 of the chip must
correspond to socket 1. Also be sure to
prevent static discharges of your body to
the computer.
Irving Chaiet, 25 Cherry Hill Rd., New Paltz, NY
12561.
References for Troubleshooting
The following articles on general hard-
ware background and on hardware prob-
lems may be of further help.
SYNC
“Adding an LED Load Monitor to the
ZX80 (MicroAce),” (1:1, p. 38).
“Four Tips for MicroAce Owners,” (1:2,
Pod
“Using the MicroAce with Sinclair
Accessories,” (1:2, p. 10).
“First Aid for Your Keyboard,” (1:3, p.
3).
“Key Click Generator,“ (1:3, p. 40).
“The ZX80 Keyboard,” (1:3, p. 42).
“A Parallel Interface for the ZX80/
MicroAce Computer,” (1:4, p. 38).
“Thick Black Bars,” (1:6, p. 2).
“Cecil Bridges LED Load Monitor,”
(1:6, p. 2).
"Experiments in Memory and I/O
Expansion,” (1:6, p. 20).
“Hardware Helpers,” (2:1, p. 28).
“4K/8K ROMs in One ZX80,” (2:2, p.
40).
“Getting Loaded,” (2:2, p. 41).
“Two-Switch Human Interface for the
Communicative Impaired,” (2:3, p. 23).
“Keyboard/System Conversion: The
First 40/1 Keys,” (2:3, p. 28).
Syntax
“8K ROM Modification,” (2:4, p. 2).
“ZZ Zap! NS74LS365,” (2:4, p. 6).
“Erratic Keyboard Entries,” (2:4, p. 7).
“All Purpose Beeper,” (2:6, p. 4).
“Pull-up Resistors — Keyboard," (2:8, p.
8).
“ZX80 Logic States of IC’s,” (2:9, p. 2).
"Video Sync Information and Tape
Recording Loading Solutions," (2:9, p.
11).
"Trouble Shooting— The Effect of
Removal of Each Chip from the Com-
puter (incl. chart of equivalent ZX80/
MicroAce IC numbers),” (2:10, p. 3).
"Power Plug Blinking Characters,"
(2:10, p. 9).
“SABRE Info on EPROM,” (2:11, p. 1).
"Improve Video Driver," (2:12, p. 3).
Byte Magazine
“Memory Expansion for the ZX80,”
(Jan. 1982, p. 216).
“Add Full Size Keyboard,” (Mar. 1982,
p. 256).
“Adding a Reset Key,” (Mar. 1982, p.
256). a”
SYNC Magazine
LET YOUR ZX81-TIMEX 1000 WORK FOR YOU.
All programs:
On cassette and require 16K Ram.
Are menu driven and save on tape automatically.
SALES FILE:
Will hold up to 125 products with their wholesale and retail prices.
Separates and totals wholesale and retail prices and shows the amount of profit
in up to 25 different accounts.
Records inventory automatically or may be changed manually. Keeps a running
total of sales tax.
Has a cash register mode which will identify, total and add sales tax while it
automatically does your bookkeeping.
*** A must for any small business.***
CHECKING:
Lists up to 30 deposits showing amount of deposit and date entered.
Lists up to 100 checks and displays check number, date and to whom check
was written.
Lists by account the total of the checks written to any given account.
Keeps a running total of checks written and the balance left in your account.
***Great for tax records.*** $9.
MAILING LIST:
Holds up to 100 names, addresses and telephone numbers.
Search by name, city, zip code, or phone number to find any address or phone
number quickly.
Lists all names.
Changes or deletes.
***Christmas cards are a snap with this program.***
INVENTORY (1)
May be used for every thing from keeping an accurate inventory for your
business, to your personal record collection.
Holds up to 150 items with comments for each.
Comments may be used for serial numbers, dates, prices or location.
List all items, search for a single item, change or delete any item.
INVENTORY (2)
Same as above without comments.
***Holds 300 Items.***
Three $9.95 programs for 24.95
Add $1.00 per tape shipping. IN Res. add 4% sales tax.
Send certified check or money order to:
HEATH COMPUTER SERVICES
950 East 52 South
GREENTOWN, IN 46936
317-628-3130
SOFTWARE BY
C.E.D.CORPORATION
E-Z BOOKKEEPING FOR SMALL BUSINESS (TAKES LESS
THAN Y HOUR PER MONTH). ALSO GOOD FOR
HOUSEHOLD BUDGETING.
CHECKING ACCOUNT (MAKES CHILDS PLAY OF THIS
JOB)
BY-IT-SELF ITS GREAT BUT IT WAS DESIGNED TO WORK
WITH E-Z BOOKKEEPING
MACHINE LANGUAGE NIT-PICK (GREAT FOR LEARNING
ASSEMBLY LANGUAGE PROGRAMING)
WORD PROCESSOR (IT WAS USED TO WRITE THIS AD)
ORDER FROM C.E.D. CORPORATION
P.O. BOX 222, SALEM, WISCONSIN 53168
PRICE LIST
TAPE LIST BOTH
E-Z BOOKKEEPING $19.95 $895 $27.95
CHECKING ACCOUNT $9.95 $595 $14.95
ABOVE TWO AS A
PACKAGE $41.95
M.L. NIT-PICK $18.95 $7.95 $25.95
WORD PROCESSOR $18.95 $795 $25.95
SPECIFY ZX80-1 OR TRS 80 COLOR COMPUTER
ZX80-1'S NEED 16K RAM
TRS 80 NEEDS 16K RAM
ALL OF OUR PROGRAMS ARE MENU DRIVEN AND ALL
DATA CAN BE STORED ON TAPE AND OR SENT TO ALINE
PRINTER
WE HAVE TELEPHONE SUPPORT FOR PROBLEMS OR
QUESTIONS
CALL (414) 276-8787
MOLDED. OF STURDY, =< BEIGE ABS, IHE ZC
ORGANIZER CONCEALS ALL THE ZX81 AND
CASSETTE RECORDER CABLES, YET YOUR
COMPUTER AND RECORDER ARE READY FOR
INSTANT USE. SPACE IS ALSO PROVIDED
FOR ADD ON MEMORIES SUCH AS THE 16K
SINCLAIR, OR 64K MEMOTEK.
GIVE YOUR ZX81 IT'S OWN HOME -
JUST $14.95 + $2 SHIPPING/HANDLING
SEND CHECK OR MONEY ORDER TO:
RUSKRAFT ENGINEERING
P.O. BOX 306, DEPT. A
TINLEY PARK, IL.60477
PLEASE ALLOW 4 TO 6 WEEKS FOR DEL.
IT'S HERE!!!
THE NEW KEYBOARD YOU'VE BEEN WAITING FOR!
A 60 KEY TACTILE FEEL KEYBOARD THAT PLUGS
INTO ZX-81 OR TIMEX SINCLAIR 1000. INCLUDES
ALL SILKSCREEN LEGENDS IN 3 COLORS.
GRAPHICS AND LEGENDS MOULDED IN KEYTOPS.
8 ADDITIONAL KEYS FOR EDIT, DELETE, QUOTE,
FUNCTION,
MEASURES 10"X4". HAS 5" SPACE BAR, TWO SHIFT
KEYS AND A NUMERIC KEY PAD.
$70.00 mass RESIDENTS ADD
5% SALES TAX
SHIPPING & HANDLING $4.00 PER UNIT
DELIVERY 3-6 WEEKS.
QUANTITY DISCOUNTS FOR USER GROUPS.
ACCEPT M/C, VISA #s. INCLUDE EXP. DATE 4 SIG-
NATURE. FOR MORE INFORMATON SEND SASE OR TO
ORDER SEND CHECK OR MONEY ORDER TO:
E-ZKEY
SUITE 75
711 SOUTHERN ARTERY
QUINCY, MASS 02169
EDSON ELECTRONICS OFFERS
Educational programs for grades
1-4 that reinforce what they learn in
school. We also offer a digital dis-
play load monitor for monitoring
data from the cassette to the
computer.
Write to
Edson Electronics
P.O. Box 151211
Tampa, Fl. 33684
for free info.
ZX81 Software: Plotter 1 — A sophisticated routine
that plots and graphs any function.
(16K) $9.99 (U.S.)
Two Handed Euchre—Challenge the computer in this
entertaining and skillful game. (64K) $14.99 (U.S.)
T2 oy sal aa
28 Shiple ie le
Weston, ntario, Canada.
M9R-3H8
ZX-80 8K ROM USERS
Completely expand your ZX-80 with
8K Rom to a ZX-81 with full use of Fast
and Slow. Smooth flicker free per-
formance!
Complete Kit: $32.50 & $2.50 postage &
handling; PCB only $19.95 & $1.25
p&h; Parts Kit Only $12.55 & $1.25 p&h.
The Expandable ZX-80 and ZX-81
A book of hardware projects that you
can build yourself, from memory ex-
pansion to speech synthesis. Only
$9.95 & $1.25 p&h.
Program writers: We publish software
and complete books. Write for details.
COMPUTER ENGINEERING SERVICES
The Jarrett Company
P.O. BOX 1222
SHOW LOW, ARIZONA 85901
(Dealers Inquiries Invited)
CUSTOM ATTACHE CASE
FORM FIT FOR ZX80/81,
TIMEX SINCLAIR 1000 AND
HARDWARE. FOR INFORMATION
SEND SASE. TO:
COMPUTA-DEK
6009 KENWOOD DRIVE
NASHVILLE, TENNESSEE 37215
ZX81/16K
ADVENTURE GAME — $9.00
With cassette and manual
ADVENTURE GAMES
# 10-35 St.
Des. Moines, la 50312
Keyboard Bleeper — no soldering required. $19.00
total.
Loading Aid — ZX80/ZX81/timex 1000 $21.00 total.
T-Shirts — red “Sinclair ZX81" on black. State size.
$7.00 total.
Fulcrum Products, Dept. U
Hillside Steep Lane
Findon, W. Sussex, England
BN 14 ONF
90
8K ROM Updates
In the first issues of SYNC the programs
were all for the 4K ROM. When the 8K
ROM became available, we tried
wherever possible to provide listings for
both ROMs. Since we have had requests
from readers for updated versions of some
of the programs we published earlier, we
will include these from time to time.
Translated to 8K ROM by James Grosjean, 50
Kings Rd., Chatham, NJ 07928.
Hurkle
Laura McLauglin
The Hurkle is hiding deep in the forest
and you must find it by logical deduction.
Type in the program, hit RUN and
ENTER. The prompts will call for the
input of two coordinates (X,Y) corres-
ponding to a point on a 10x10 grid. The
computer will then tell you in which
direction the Hurkle is hiding. Again you
enter a new set of coordinates and con-
tinue until you have found the Hurkle or
used up your five guesses. The program
fits in 1K RAM. With sufficient RAM,
Hurkle could be expanded to show the
grid on the screen and record your
entries.
1 CLS
2 LET R=INT (RND#18) 34
4 LET B-INT 1RMOsi1>1
6 FOR K=i TO $5
S PRINT "GUESS NUMBER "iK
10 PRINT “x COORD’?
12 INPUT X
14 PRINT “Y CQQRE?
ues INPUT Y ;
IF RBS (X-RA219+ABS ÜCy-Brze TH
EN *SoTa £2
28 CL
22 PRINT “X=",X," Y=";
24 Gosua se
26 NEXT K ^
S38 PRINT “SORRY, THAT IS 5 GUE
“PLAY AGAIN?”
“yOu FOUND HIM IN “¿A
o0 PRINT “Go “;
Se IF Y=B THEN GoTo
S4 IF Yi THEN Gore
oe PRINT "S3SOUTH',;
SG GOTO se
BM
i
Sa PRINT
Ge IF x=A THEN GOTO 72
CX IF X20 THEN Cra FR
66 PRINT “ses
74 RETURN
Castle Doors
Weldon J. Horton, Ph.D.
Castle Doors is an adventure game that
presents a new challenge with each play-
ing and easy adjustment of the difficulty
level. The object is to defeat the wizard.
Type in the program, hit RUN, and
ENTER. The display will show your
strength and ask whether you want to
open a door or fight the wizard. The
2 PRINT
ieee PRINT “WELCOME TO CASTLE DG
o LET B=RND +300
19 LET C=INT (RND#5@) +1
e
OPEN A DOOR 5: F
22 PRINT “a
IGHT WIZARD"
26 LET D=INT (RNDO#5) +1
25 LET A=
30 LET E=RND#50+1
32 LET F=INT (RND21@83
34 LET G=INT (RAND:25S) +1
38 INPUT OG
40 CLS
41 IF 0O=5 THEN GOTO 176
42 LET A=INT (RND£r£íDr:104-10)) +1
(D-FELR) x2
"CYCLOPS”
46 LET Ag="“HNITCH"
47 GOTO 6
45 LET As="“DRAGON*
493 GOTO €e
S@ LET A#=“GARGOYLE™
S1 GoTo en
S2 LET Af=" ZOMBIE"
S3 GOTO 66
62 PRINT
a PRINT “YOUR OPPONENT IS A
¿A
72e GOSUB 200
58 PRINT "ENTER Lo ELOSHE 2:
BRIBE 3: RUN"
34d INPUT N
56 Cis
58 IF N=2 THEN GOTO 124
390 IF N=3 THEN GOTO 148
22 IF C<A THEN GOTO 176
a 208
112 IF &>C THEN GOTO 394
114 IF @>=A THEN LET C=C+6
display will continue to confront you with
options which will either use up your
strength or add to your strength. When
you feel your strength is sufficient, you
may take on the wizard.
The variables in lines 26-34 may be
changed to provide different challenge
levels.
@>=A THEN PRINT "YOU uit
ADUENTURER"
Q<A THEN LET C-C-G
TE THEN PRINT “YOU LOSE
IF P>=E THEN LET C=C-P+G
IF P>=E THEN PRINT “ACCEPTE
IF P<E THEN PRINT “REFUSED”
IF P<E THEN GOTO 68
GOTo 12
27 THEN GOTO 176
154 PRINT “YOU GOT ANAY"
156 LET C=C-INT (RNOD#15) +1
GOTO 12
PRINT
162 PRINT
i64 IF D=6 THEN PRINT “SAVE PRI
NCESS AND GAIN S@ POINTS"
166 IF D=6 THEN LET C=C+59
168 IF =7 THEN PRINT "A FRIRY
GIVES YOU A POTION WHICHDGUBLES
178 IF D=7 THEN LET C=Cx2
172 IF D=8 THEN PRINT “A GIANT
SAT TAKES YOU TO ANOTHERDOQGR”
174 GOTO 12
176 PRINT
178 PRINT
150 IF C>=5 THEN PRINT “You
LED THE VUIZARD-YOU NIN”
152 IF C«B OR C<R OR C<2 DR =e
THEN PRINT “YOU FOUGHT WELL BUT
She POE QUERY
“YOUR STRENGTH IS "2
PRINT
IF C:ł THEN GOTO 152
206 RETURN
SYNC Magazine
ZX81 2K UPGRADE KIT $15
DOUBLE YOUR 2X
MEMORY TO 2K ON-
BOARD. KIT INCLUDES
ALL REQUIRED
COMPONENTS AND
DETAILED ILLUSTRATED
MANUAL. COMPATIBLE
WITH 1 OR 2 CHIPBOARDS.
$2 REBATE FOR YOUR
OLD CHIPS.
J. BALOGH, P.O. BOX 1319
STATE COLLEGE, PA.
16801
SINCLAIR ZX81 & TS1000 SOFTWARE
Fifty games for less than $2 ea.
Send SASE for FREE catalog to:
BIOCAL SOFTWARE
340 Cypress Dr.
Fairfax, Calif. 94930
16K ZX-81 SOFTWARE
FOR THE HOME:
CHECKBOOK BALANCE
ENERGY ANALYSIS
VIDEO CALC
EDUCATIONAL:
ARITHMETIC TUTOR
ALGEBRA TUTOR
SPANISH TRANSLATOR
ENTERTAINMENT:
ANIMAL QUIZ
PLAY THE MARKET
ENCRYPTOR
EACH ON A HIGH QUALITY C-10
CASSETTE @$9.95 EACH.
SEND SASE FOR PROGRAM
DESCRIPTIONS
P & BSOFTWARE
1155 E. MALIBU DRIVE
TEMPE AZ 85282
OTHELLO FOR 1K
GRAPHICS, HIGH-SKILL
PLAYING ALGORITHM
PROGRAM LISTING — $2.00
INTELLECTUAL GAMES
193 PEACEABLE ST.
RIDGEFIELD, CT 06877
IMPORTED GAME CASSETTES
ZX81 16K $14.95 EACH
“TRADER JACK” FANTASTIC FUN GAME.
BUSINESS LOGIC — SOUTH PACIFIC LOCAL.
“ZX81 MONOPOLY” UP TO 6 PLAYERS.
SPECIFY EITHER SPANISH, BRITISH OR
AMERICAN LANGUAGE VERSION.
SAVAGE SOFTWARE, PO BOX 441
TITUSVILLE, FL. 32780
September/October 1982
Nicomachus
David Ahl
Type in the program, press RUN, and
ENTER. The prompts on the screen will
tell you what to do. Type in your entry
followed by ENTER. The computer will
then figure out your number by logical
deduction. The program fits in 1K RAM,
and runs better in SLOW mode.
10 LET R="UHEN DIVIDED BY "
20 LET R$=" ITS REMAINDER IS?
30 dra “THINK OF A NUMBER FR
$7 3;,05;
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Wi
B
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Ml
BS;
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S eios paie
"LET ME THINK A MOMEN
140 LET Y=7B:+RA+21xB+15:xC
159 IF ¥<186 THEN GOTO 139
160 LEF Y=Y-1085
170 GOTO 158
150 PRINT "YOUR NUMBER WAS “jY;
"S; RIGHT?
199 INPUT AS
210 IF CODE AS$=62 THEN PRINT "Fi
220 IF CODE A$=S51 THEN da ES ^
CY ^N
240 INPUT D
250 CLS
260 RUN
Widget
Gary McGath
To play Widget type in the program,
press RUN and ENTER. The screen
prompts call for you to make executive
decisions. Type in your decision and hit
ENTER. After computing your decision,
your ZX81 will post your new financial
position and the number of many months
you have been in business. The object of
Widget is to avoid bankruptcy. The pro-
gram requires a 2K machine.
HAS
pas BG Pp
3 S
a
C
L
110 PRINT "MONTH d dE
120 LET Z=Z+1
à a BUT. "YOU HAVE’: TAB 16; "3"
"310 PRINT TRE 8;P;" PLAN
320 PRINT TAS 8; I; ‘aa UIDGETS"
¿330 PRINT "LAST MONTH You SOLD
358 TF M<1@6@ THEN cOTO 410
360 PRINT “BUY A PLANT?
370 INPUT YS
3398 IF vY5$4»5''Y'" THEN GOTO 418
390 LEF P=P+1
409 LET M=M4-iua
¿10 PRINT “AD BUDGET IN 18825 7
420 INPUT 6
430 IF BxiQ5»HM THEN GaTa 428
140 LEF M=M-EBx1u
459 PRINT “PRODUCTION IN 1885 7
470 INPUT WU
490 IF Niate THEN cOTO 478
sað LET SZINT SAINT (RHD 4342}:
518 IF 2:<5 THEN GOTO 558
E Sut (8-63 #5
558 IF Bx2 TREN eo a
550 LET S5=3+1B-212 LU ss
570 LET B=2
500 LET S=5+8sa8
510 IF S>I THEN LET S=I
520 LET M=H4+S21a
6389 LET I-I-5
o40 LET M-zH-2298xP-2ü
550 LET M=M- (U-32 4S
509 IF M>=8 THEN GOTO i182
sad PRINT “YOU ARE SANKRUPT.”
SYNC-hronizing
Education and Games
A newsletter filled with games
and ideas for the Sinclair.
A Quarterly publication that is a
must for all Sinclair owners.
Send $7.00 U.S. $8.00
Canadian to:
SYNC-hronizing Education
and Games
c/o Henry Svec
668 Sherene Terrace
London Ontario
Canada N6H 3K1
(Cheques payable to Henry Svec)
IS YOUR FAMILY TIRED
OF PLAYING GAMES ON
YOUR MICRO?
ARE YOU LOOKING FOR WAYS
OF CHALLENGING YOUR
INTELLECT?
QUIZ WIZ IS THE SOLUTION!
Through QUIZ WIZ you can test
your family's general knowledge
on your 16K ZX81.
INTRODUCTORY OFFER! FIRST ISSUE
Two Quizzes Per Cassette $4.37.
OR BETTER YET! Full Year Subscription
Six Issues-Six Cassettes $22.47.
Send check or money order to:
SG
Box 553
Mechanicsville, Virginia 231 1 1
Virginia Residents add 4% sales tax.
Overseas orders add $1.00.
ADD ON MEMORY
FOR ZX
16K memory assembled and
tested. No extra power supply
needed. 90 day warranty on
parts and labor.
$45.95 POSTPAID
Check or money order only.
California residents add 696.
KB ENTERPRISES
8211 VALDOSTA AVE.
SAN DIEGO, CALIFORNIA
92126
aed Loe
The “Resources” column lists new
products for Sinclair users. Suppliers and
users are invited to send brief product
descriptions and details for ordering to:
Resources, SYNC, 39 E. Hanover Ave.,
Morris Plains, NJ 07950.
User Groups
e Kaiserslautern, Germany ZX81 Users
Group. Just being started. Contact:
Tom White
HG 21st SUPCOM
ACSRM - IRD
APO NY 09325
Phone: 2221-7432
e The Sinclair Users Group of San Diego.
For information contact:
Robert Jorgenson
3814 Coleman Ave.
San Diego, CA 92154
User Groups Forming
e Any Portland, Oregon, area users inter-
ested in forming a group? Contact:
J. E. De Groot
2146 N.W. Johnson St., 108
Portland, OR 97210
Business/
Household Programs
e ZX Phone Book. Holds 720 names
with edit functions of ADD, CHANGE,
DELETE, and SAVE; search by name
or category; can be used for other
information. 16K RAM. Hard copy
listing with thorough documentation:
$4.95
e Sort-a ZX81. Collating tool; counts
and files thousands of items in up to 29
categories on just 1K RAM; listing and
notes show how to use your ZX81 as a
home and office tool. Hard copy listing
with thorough documentation: $4.95.
Thomas B. Woods
PO Box 64
Jefferson, NH 03583
* Data Storage and Display System. Stores
up to 60 data points in a file, e.g., stock
prices, profit-loss data, experimental
data; allows file crunching for plotting;
92
up to 25 files can be saved under user-
defined titles; recalled in tabular or
graph form; menu lists 9 jobs; expand-
able with additional cassettes. 8K ROM;
16K RAM. $14.75 plus $1.25 s&h.
ZX-Panding, Ltd.
PO Box 25
Newton, NC 28658
Educational Programs
* Vocab Builder for the ZX81. 60 words
per cassette; 2 modes; definitions and
quiz; for teens and adults. 16K RAM.
$9.50.
Charles Bucher
132 E. Pasco Lane
Cocoa Beach, FL 32931
Games
e ZX81 Bomber. Drop bombs and two
types of missiles on the enemy; graphics;
points and percentage; full documen-
tation and instructions. 8K ROM; IK
RAM. Program: $1.00 plus SASE.
Cassette: $3 plus $1 s&h.
Rimas Buntinas
7440 N. Rockwell
Chicago, IL 60645
Trader Jack. You are captain of your
own trading vessel sailing the South
Pacific; buy supplies; fight storms and
volcanos; trade your cargo, hopefully
for a profit. 8K ROM; 16K RAM. Also
ZX81 Monopoly in Spanish, American,
or British versions. Each game on cas-
sette: $14.95.
Savage Software
PO Box 892
New Smyrna Beach, FL 32069
Pick em. Program to attempt to predict
outcome of national football league
games and even the point spread;
accepts information available from most
daily newspapers. 8K ROM; 16K RAM.
Cassette: $9.95 plus $1.50 s&h.
Stuart Software
25381-G Alicia Pkwy., Suite 316
Laguna Hills, CA 92653
Mad Dog Tank Blaster. Mammoth pro-
gram with routines useful in your own
programming. Wild tank moves through
grid-like maze blasting all the way; your
man must put a mine in its path without
getting shot, run over, or blown up by
the mine. Hard copy listings with
thorough documentation to teach pro-
gramming. 16K RAM. $6.95.
Thomas B. Woods
Box 64
Jefferson, NH 03583
Arcade excitement on your 1K or 2K
ZX81. All programs have moving graph-
ics; sold as listings. Pickle Man: $2;
Tempestuous Battle: $2; ICBM Barrage:
$2; Monkey Barrels: $2; Defense Wave:
$1.50; Evade: $1; Lander-X: $1.50. Add
$0.30 s&h.
Panero Software
3309 Lewis Ave.
Long Beach, CA 90807
Game Pack for the ZX81. Bomber
(move the bomb sight over the target,
very fast); Missile (destroy the missiles
before they hit your spaceship); Auto 3-
D (enter 4 numbers; ZX81 will draw
tunnels and spirals and much more
depending on numbers); Speed Draw
(the ZX81 starts a line; control it by the
right keys to produce all sorts of
pictures). 8& ROM; 1K RAM. AII four
on one cassette: $5 plus $3 s&h.
Mark E. Rogers
553 Melrose Dr.
LaPlace, LA 70068
18 Hole Golf. Graphics display of each
hole, moving ball, 3 types of hazards; 4
player capability; final score card dis-
play; 3 different courses. 8K ROM; 16K
RAM. Cassette: $10.
R. Midura
19 Merrifield St.
Worcester, MA 01605
Graphics Programs
e Memopak High Resolution Graphics.
Contains 2K EPROM monitor, holding
full range of graphics subroutines called
up by USR or machine code; gives 192
x 248 pixels. Video pages: each requires
about 6.5K RAM; memory and bit
mapped; can be located anywhere in
available RAM. $149.95.
Memotech
7550 West Yale Ave., Suite 200 |
Denver, CO 80227 |
SYNC Magazine
SENTING
mie” ZX KLIK - KEYBOARD
IF YOU ARE like many ZX81 users and are fed up with the
dead ‘touch sensitive’ key pad then consider the advan-
tages of the new KEMPSTON KLIK-KEYBOARD. This is
a genuine push button keyboard which has been
designed as an exact replacement, being no larger than
the existing key pad, but offering all the advantages of a
KEMPSTON MICRO ELECTRONICS
full size keyboard. Consider these facts:
e Fits on to the ZX81.
@No soldering needed on the assembled version
(just plug in)
eNo trailing wires.
e No special case required.
ePositive feedback from keys.
@Full two colour legends supplied.
eFull back-up service offered, including fitting.
sensitive keypad.
adhesive pads and a full set of instructions.
Also available from our range of products is a
Parallel User I/O post £16.50 built & tested. Gives
161/0 lines to drive light relays, motors etc. Many
already sold to education. Keyboard bleeper £8.95
built.
8K ROM, 16K RAM Sinclair
BLACKJACK - Practice your
Strategy. Hit, stand, double
with this Nevada casino game.
editing, storage and display.
Recall pages of text without
line.
to organize programs and ease
loading. Both TEXT and PRODIR
for $10
Prices include shipping.
Send check tos
Peak, P.O, Box 383,
San Carlos, CA 94070
This is a genuine 40-key, push button keyboard which fits
into the recess formed after peeling off the existing touch
The kit comes with a precision drilled P.C.B. finished in
matt black, 40 keys, 2 colour legends, connecting tails,
Cassette Software for the
down, split and take insurance
Plays out a complete deck. $10
TEXT - A program for easy text
splitting words at the end of a
PRODIR - A programmed directory
Your Name and Address |
Unit price
$45.00| |
$52.00| |
pr
Please allow 14 days for delivery.
Kempston Micro Electronics
60 Adamson Court, Hillgcounds Road, Kempston.Beds.MK42 BQZ
Proprietor A. Pandaal, B.Sc., P.G. Cert. Ed.
MAKE YOUR SINCLAIR
A PORTABLE COMPUTER SYSTEM
MAC (MOHR 4 Associates Corporation) Now Of-
fers You A Durable, High Impact ABS Plastic Brief-
case That Measures 17?" X 1214" X 4/2". Wired For
110-60HZ And Ready To Be Used!
You Merely Insert Your Sinclair Components (In-
cluding Printer) In the Preformed Cavities And
BINGO You Have A Portable Computer System.
The Briefcase Has Slots For Tapes, Coax Cable
And The TV Adapter.
$149.95 Includes Shipping & Handling.
Kansas Residents add 396 Sales Tax.
TO ORDER
SEND CHECK OR MONEY ORDER
MOHR & ASSOCIATES CORP.
645 N. Baltimore
Derby, KS 67037
(316) 788-1526/788-3165
MC/VISA ACCEPTED
SALE -Z»XB7 EDGE
CONNECTOR $4.23
5/$23-ADD 5OtEA.
INTRODUCING:
Printers
e MW 100 Printer. Available now. Prints
on plain paper roll, 1 3/4 inches wide;
standard tape and ribbon obtainable at
office equipment and electronics stores.
For details:
Mindware, Inc.
PTX-1/0: @ro16
PORT EXPANDABLE
INPUT -OUTPUT PORT
SYSTEM. COMMANDS
IN BASIC.KEYBOARD
PORT,D^/A,A/D,FREG
UENCY GENERATOR...
USE YOUR COIVIPUTER
TO IT'S MAXIMUM!!! K . 70 Boston Post Rd.
SASE GETS DETAILS Catalogs/Directories/ Wayland, MA 01778
POWERTRONIX Product Lists M P
25 E23ST.BAYONNE e Programs for the ZX81. Games, Interfaces
N.J. 07002 USA business, household, statistics, cards,
aids, horse racing, and other general
items. Free catalog.
UAS
PO Box 612
Haddonfield, NJ 08033
e Memopak Centronics Parallel Printer
Interface. Enables ZX81 to be used with
a wide range of dot matrix and daisy-
wheel printers. Resident software gives
ASCII character set. $94.95.
ZX TYPING TUTOR
e LEARN ALPHA NUMERIC KEYBOARD
e THREE SKILL LEVELS
e INSTANT FEEDBACK AND FINAL SCORE
e GET THIS HIGH PERFORMANCE 8K/16K
LISTING AT BIG SAVINGS.
e ONLY $4.95 FROM:
MICRO-TECH
1019 BRANDON LAKES AVE.
VALRICO, FLORIDA 33594
MARKETING SERVICES
For those unfamiliar with techniques in mar-
keting methodology.
Send us your original programs for review.
Send S.A.S.E. for full details, now.
Timex Software Company
Box 48595
Chicago, Illinois 60648-0595
The Troiano Software Company is now
offering for the ZX81 a graphics, games,
accounting, math and utility package
with 12 programs in all! Only $4.00.
Troiano Software Company
PO Box 40
Nesconset, New York 11767
ZX81 Assembler
2 Pass Standard Mnemonics,
Symbolic expressions, Decimal /
Hexadecimal, 12K Basic and
machine code.
ZX81 Disassembler
Standard Mnemonics, Decimal / HEX
$18.00 for both programs postpaid
Bob Berch
19 Jaques St.
Rochester, N.Y. 14620
94
>
Game, utility, household programs. 16K
RAM/1K RAM. For details send SASE
(postage $.40).
Gampper
Zollamtstrasse 52
675 Kaiserslautern
West Germany
The Sinclair Computer Family
Sourcebook. Lists over 500 programs,
books, accessories from over 80 manu-
facturers. $4.95 plus $1.25 s&h (add 4%
tax in Virginia).
Atlantic Computer Products
PO Box 936
Norfolk, VA 23501
Howard Hein is compiling a directory
of services and supplies for the Timex/
Sinclair 1000. He invites readers to
supply information on: hardware and
software suppliers; hardware and soft-
ware projects (including listings); user
groups; newsletters; reviews in maga-
zines and books; suppliers of training;
shows and festivals. Submissions and
comments to:
Howard Hein
33 Oak Lane
Mt. Lakes, NJ 07046
RAM Expansion
Memopak 16K RAM. Accepts further
memory units plugged in “piggy-back”
fashion (Memopak 16K, Memopak 32K,
or Sinclair 16K) and other add-on
peripherals. $59.95.
Memopak 32K RAM. Full 32K RAM
directly addressable. Accepts Memopak
16K RAM as plug-in. $99.95.
Memotech
7550 West Yale Ave., Suite 200
Denver, CO 80227
Memotech
7550 West Yale Ave., Suite 200
Denver, CO 80227
ZX99 Automatic Tape Control. Full
software control of up to four tape decks
(two for loading; two for saving) to mix
and modify files; uses tape for data
storage; automatic tape copy; diagnostic
information for best recording; RS-232-
C interface to connect to any such serial
printer using standard ASCII; 2K ROM
extends the ZX81 8K ROM and
accessed by USR. $150.
Data-assette
H.S.W. £ S., Inc.
52 South 3rd St.
Oxford, PA 19363
(215) 932-3626
Keyboards
e ZX80/1 Keyboard. Keytops finger
shape molded; characters for the ZX
keyboard printed in two colors on key-
tops as per your ZX80/1; repeat key;
black plastic molded case available (can
be purchased separately); 12-inch ribbon
cable attached by 15 solder connections;
full instructions. $75.
Data-assette
H.S.W. € S., Inc.
52 South 3rd St.
Oxford, PA 19363
(215) 932-3626
44 key tactile keyboard; plugs into ZX81
or Timex/Sinclair 1000; all graphics
included; EDIT, DELETE, ”, and
FUNCTION do not require shift. $70
plus $4 s&h (add 4% tax for Massa-
chusetts
E Z Key
Suite 75, 711 Southern Artery
Quincy, MA 02169
SYNC Magazine
* Keyboard overlay. Gives tactile help in
making keystroke entry; stops missed
keys; speeds program entry; simple to
install. $3.95.
P. Hargrave
Site V, R.R. 4
Nanaimo, B.C.
Canada V9R 5X9
* E-Z Key 44. Hear a click and feel a snap
for every key pressed; 4 special keys
have electronic control to eliminate
need to use shift key (DELETE, EDIT,
”, FUNCTION); accesses all graphics
and functions; no wiring required; just
plug it in; adaptable to ZX80 or Micro-
Ace; schematic and instructions. $70
plus $4 s&h (add 4% tax for
Massachusetts.
E-Z Key
Suite 75
711 Southern Artery
Quincy, MA 02169
Hardware Improvements
e ZX81 Improved Heatsink. Prevent sys-
tem crashes caused by overheating of
voltage regulator; no modification of
appearance or function of the ZX81
needed; installed in minutes. $10.
B. Sanzone
289 Baxter Lane
Milford, CT 06460
* End edge connector tarnish problems.
Electro-plate the fingers with 24 karat
gold. $15 plus $3.75 s&h for first item;
$10 plus $2.75 for any additional item
with the same order. Do not send the
product you want plated now. Instead
send SASE for full details first.
Matthew Zenkar
142 Holcroft Rd.
Rochester, NY 14612
System Expansion
eSystem expansion kit. Install permanent
system utilities such as machine lan-
guage or service routines in up to 8K
memory that is not lost when you reset
or turn off your ZX81; compatible with
16K RAM packs. Full details and all
components including one 2K
HM6116P-3 CMOS RAM: $29.95 plus
$1.95 s&h. PC board alone, masked and
silkscreened: $15 postpaid. Additional
2K HM6116P-3 (150 ns): $9 each.
Hunter
1630 Forest Hills Dr.
Okemos, MI 48864
September/October 1982
Tape Accessories
e Winky Board Cassette Loader/Dupli-
cator Interface. Makes loading easy;
includes LED level monitor, earphone
eavesdropper and interference filter,
circuits for direct copying of any cas-
sette. Kit: $12; assembled and. tested
unit: $18. U.S. postpaid; overseas: add
$2. Free information.
G. Russell
RD 1, Box 539
Centre Hall, PA 16828
* ZX Loading Aid. Circuit detects and
shows signal level on two LEDs to
enable you to distinguish program, intro-
ductory buzz, silence, voice overs; in
small black metal box 90x35x30mm with
two 3.5mm sockets and two 3.5mm
jacks; connects between tape player and
computer. 1759.95 (incl. s&h and VAT);
$21. Specify which computer you will
use it on.
Fulcrum Products
"Hillside" Steep Lane, Findon
Worthing, West Sussex BN14 OUF
United Kingdom
e Chirper module. Gives acoustic feed-
back on keystrokes as a variable chirp
that remains on until the ZX81 is ready
for another entry; produces sound while
program runs; sounds can be program-
med either in Basic or machine code;
fits inside ZX81; solder 3 wires. $9.95.
Audiograph Co.
3584 Leroy
Ann Arbor, MI 48103
T-Shirts
e T-Shirts and Sweatshirts. SoftWEAR for
the ZX81 owner. T-shirts with round
neck and short sleeves; sweatshirts with
long sleeves and heavy weight fleecy
lining. Red lettering "Sinclair ZX81" on
black or white shirts. Adults: 34", small;
36", medium; 38-40", large; 42-44", extra
large. Children: 24”, 26”, 28”, 30”, 32”.
T-shirts: £3.25 or $7; sweatshirts: £6.99
or $16.
Fulcrum Products
Hillside, Steep Lane
Findon, Worthing
West Sussex BN14 OUF
United Kingdom
Video Upgrade
e Video Upgrade Kit. For ZX80 8K ROM;
smooth flicker free video; performance
is exactly that of the ZX81; easy assem-
bly and installation inside the ZX80.
$32.50 plus $2.50 s&h.
: Computer Engineering Services
PO Box 1222
Show Low, AR 85901
(602) 537-7522
8K ROM; 16K, 1K. Games, Utilities,
Tech prog., Household prog. &
more. For details send SASE to:
NGM INC.
P.O. BOX 18702
OKLA CITY, OK
73154
COLOURSCREEN
FOR TIRED.EYES
Fit one of our colourscreens to your
T.V. and cure those programmers
eyes. Available in 3 sizes and 5
colours.
Blue, Green,
Orange.
Small (9" x 12") $1.75
Medium (12" x 15") $2.95
Large (18" x 24") $4.50
Plus $2.00 airmail postage
Order now direct from the U.K.
Ellanbee (Graphics)
11 Lichfield Close,
Great Lumley,
Chester-L e-Street,
Co. Durham
DH3 4QH U.K.
Hed, Yellow and
ZX-81/ 1K
Listing of 5 games $2.00
Solo/2 Player Games
2 Graphic Displays,
Stock Market, Random Race,
Treasure Hunt.
Z-Games
P.O. Box 367
Ringles, N.J. 08551
CAR LOG
A new USEFUL suite of professional
programs for the ZX81 (16K). |
1.) Very simple to use with full instruc-
tions.
2.) Complete cassette record of mileage
and itemised expenses.
3.) All conceivable ratios, totals and |
projections computed.
CAR LOG is suitable for your car, your |
dad's car or your whole fleet of trucks.
Only $14.95
NIMROD SORTWARE
4 Stanley Rd.,
London, SW14 7DZ U.K.
NEW for your ZX 81
Microtronics-LR, inc.
is introducing a new
peripheral for the
Sinclair ZX 81 soon!
Watch for our ad.
VOYAGER ADVENTURE
Your space craft has landed on a barbaric planet,
attempt to save your own planet. Here you will meet
up with more than 20 different encounters. You'll
have your choice of one of over 34 billion characters
available. This adventure is huge (two sides-16K
each) and is saveable once in progress. Send $9.95
or for more, send to Chris White, 789 S. Greenbay
Rd., Lake Forest, IL. 60045.
95
PLANET FINDER FOR THE 16K TS-1000/ZX-81
MERCURY, VENUS, MARS, JUPITER and
SATURN are all visible to the naked eye. The ancients
recognized that their special quality is that they move against
the background of “fixed” stars. Predicting their movements
has been the preoccupation of geniuses for thousands of
years. Now these movements are well understood, buy only by
a few dedicated observers. Ephemeris V is designed for these
people and others (ages 12 and up) who wish to join them in
this pursuit of basic knowledge. 16K reqd.
ENTER: date, time, lat. and long. (Lat. and long. can be
perm.) Then choose a planet. In seconds Ephemeris V
responds with:
1. Azimuth and Altitude
2. Right Ascension and Declination (for astronomers)
3. Simple compass coordinates (for beginners)
4. GRAPHIC DISPLAY of planet in current
constellation
5. LOCAL sidereal (star) time to aid in finding stars,
comets, nebulas, etc.
Own or give this incredible program and reap the harvest of real
understanding forever! Comes on quality cassette with docu-
mentation. Send a money order or check for $8.00 ppd. to:
EPHEMERIS V, P.O. BOX 261, Winchester, KY 40391.
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ADErSO ooo a AI latin Ut (eani re itae 43
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PROB AUTO + Li cscs S Ee TENA OUS Quo cgi heus up inquo eats 71
Adventure AMOS 4, is Aeuciiceciagad chen e east indy 90
PRECIO EUREN A UII GISELE. ue CUIU Lg UT IMG d 43
P M LCS SET ERIT UBER, A GANE TUE A E MN EUER IOS IT 39
ACDESPOS Tech... 3 51 ario ricasel ye anais cese eas 65 `
Atlantic Computer Products .......oooooouuononnncnnnnnonono 60
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Balogh JOB: A A O AS os o 91
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Berch. Bab AAA NM AO Us deny cot and aasi 94
Boca PROT V ELS esistette exiis ore ANAE li ad aida 91
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EST COMING o otio Mie crees ale cos bos bei ope 78
leva: Computer Ware: Holt ik eere dienen eene ni 33
Comput&a-Dek.. Loi i vals doma eei rens 90
Coniputer. Conti umm. Loci oque euo ya ea aee s iiae oed 64
Computer Engineering Services........................... 90
(CODIDITEFCFRTE 11er iere side o Tto viddln dada ive ot «o ons quu rao 60
COOK DRE AAN OA NEU EET REE oo e sed Vio 51
Cos MONIS Iliana ERi euet ei saasaeeseeds 68
DR Tronics T DU up Vo RE Re ui san aus Cover 3
PICU UNE, RELOAD IE JE EDU: ST ROTE -SRSqUND. oA: 88
TARE A O ACA OA 4,5
DAV WONG A AN Aae PENAS AA re eunte 88
MAN, AE o Y T Ee ps gae O NA TON 45
Down-East COMDUTCES Lui odd A O A 76
DOWNSWAY UL ooa A edduce cat VER O ÓN 63
Driver OLIVO in ibus dades et spony eass osise sis 79
EI A duse i e gutes Wo DEDERE SUV UN NU TEE 89
Edsorm Electrons Aien ree A AAA 90
ESRI Gia pg Gu erred er eesi regios 95
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Preh Ere oit Rice REO Od nerd eoe sae cf I 78
Erop SONWALE A RSV eren NA AGS UN 61
burn O ei IO E 90
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Euron Peter, Products. uuusrerirecepeespsdero iocus 86
EOD IOS PTE decise siege Any Fiet O AE 57
$6.95 pp.
MUSIC and KALEIDOSCOPES
VIRTUOSO. A music synthesis program for the
Timex/Sinclair and ZX81 with 2K or more. NO
MUSIC KNOWLEDGE NECESSARY! 96 notes.
range from put put to above treble clef, any tempo.
Whole to 32nd notes. Songs may be saved for
future use. Required hardware? - - Your cassette
recorder. $6.95 pp.
PLAYER ZX81. A less versatile music program for
1K memory. To: Music knowledge unnecessary. $6.95 pp.
SQUARES and CROSSES, Kaleidoscopic
simulations-for the same machines. 1K or more.
All on standard cassette. Guaranteed to load.
Music programs include random sound listing or
save copy. Add $3.00 each, outside U.S.
. Mr./Mrs./Ms.
Address
City/State/Zip
Virtuoso $6.95
Index to Advertisers
Gladstone Electronics ........—.... 26 S 6i ees 48, 49
Hargrave P. oo iui ed. 3d ee etos t eu A 88
Haymarket SOIUWBIA eee eer recor ba Eton ciao 63
Heath Computer: Services... iore eesein ei 89
PIU iE ens ved P paese y Aca EU E 61
HIUTTICADO DIeotTURIQU.. .... coste ee etor tiae an rae ean nag 56
Independence Research.............. 4. cra veras sa ene rs 18
MANIY RESAN c... nuces ht nero ee saaie Aana SSSR 85
Intelectual OON... . (5 e eer IA ce 91
Intercompiiter, Inc. .......3....4 0. erroe Geti 13
International Publishing...............,.. 2 0: enero (nnd 31
J O SONWATE RESORTS RUE AA 90
SEU RA roro so rho DRE ERE FERIAS 82
JK Adios UI E E ees A ence T DREAM ME 16
JRS SoftWare s oerdetete eu divcosoe cu dede svo FEES aon de 12, 19
Jenn Products dle isa ole e edes ey s ire ado EINER AURA SIUE UE 45
K SofG EA A IAE eU eo lene conquest eso dn qa BRA M 46
Kt Rr OP bee A equi deiade soli INVE 91
KMLJIncorDarated .....5.. odo dpi cei qus 73
Kayde Electronic Systems ..................... erento 2
Kempston Electi 2.5 seus eer requi avia nao alioli ganó 65
Koala. SOP Be Qe css. 5 dile oA se agn Aie ce td E 84
Kopack Creations, Inc.c...—27. 55 A Xa crees 67
Lambs Software... Aes incidan ta ease qa ido ba Sade 82
Lato Léfns.....i. aas tb voce ios E OE DE I oy ore” 83
Leading Edge... inanición Cover 4
MC. Associates iussa. adest eo car Co Neo ED eco 52
E A O rev iuis EI bebo ias OS 40
Maples; WIDIant. «ouo. eerie ed eiua arena 96
Metmoteéclt 45 oereedeirsasecadéskoxee eder dócil ted aq. 9
Micto-88 oS qne ietribeeiisef cerva aaron» 73
Micro Computers Pfus;..............— 5 eR E 27
Micro Design Concepts: .::......5......cessessesoraiassecseane 56
Micro Syne 2... rea i145: santa paare ci cade nc nbi E C9 od sii senate 7
Micrá Tech ise Disce iei ves pyre HN eara A PE Fera SUA 94
a AOS ie epu RA > RN 95
Mikroen raro ariocerrinoria mado iae coda siecdenscatscegeuscg cee 57
Mohr & Associates SI oicnesvonressrr unir sonado seran orcas 93
NG M* Ine; ,...: sah condal ieee rc r ora 95
Nimrod AR OS e aa keine qaid 95
Nirad IC irreal rr iio ed 57
Non- TrIVIM ISOBRUODS iere 655i cans cones tere pisse MPa ke 8
Nooter Stock Progtám ...........151:. ede cete seyn sd 59
DAME Da ivi EXTR caet Se ee 65
Omni Technology... as A cete A 43
LAA uo isch O dra eX apatite 46
Player ZX81 $6.95
Squares & Crosses $6.95
William Don Maples
688 Moore St.
Lakewood, CO 80215.
P. & B SofbWare....( odas bx p dir 91
Panda Software inicie oo A ipia cea So Pini 22
Eesti A A AR A AR o E e 93
POWOIGODBDE ee deo eni Fe ee Ero ee sse Pero da dh do at Tu quie 94
Reston -Publis hina: -sesasi can tiet Gei ege ate 37
Robill Products ........ orte A etna 59
Rom Pac Applications ............................ ikone Cover 2
Romark iaa ri 18
Ruskraft Engineering ..........-. eodeni qnte 89
SO Era ir EES A TE EEES 91
Savage. SoftWAare.......... 7 riesce pl eet dad éd EY D) Mu 91
SerVitfOltiQB à. eiie eastesieFenbasuis ences (el eec Lap A e oe 73
Sinclur PISOS La oo uices toco opido EN QA eqs 28
Sinclair Research. eorpore ori phe sk er epa 14, 15, 81
Sinware i oor spl tu Qi eve cra oca Id bee 84
Smart Warec ades avit died ario PPM ECKE 86
SaftClait. 4a ektet és cxx La EN eere Pire asi quta os icu) 60
Softsync INC. 1. iod cete eibr ced Quer eaa ra n ER eph S 1
Software: Master... s.. 5. d rexide iaer saia nate o save 47
Southern Computer SystemsS.......cooccccccccnocccanannnoss 25
Strategem Cybernetics ¿.isoscindncóncndonesoscosnarrcaicarao nos 64
Miet A AME A ATLA TERME I ec 93
Svec, HENLEY onere pin cotes e Netin AEE PERA 91
Synchronize: ns erii eo doen one ao anrea te uv a 32
Syn CWAFe......riris oidor pone edicion ade RARA 87
Synergistic Desi gy ie ccins..ésccondescvebdaransesdussederenssyishe 11
T.V Services sik heed ice eee 54
Thoma nicol ois ao ss te a cee 85
Time Dáta ieii oiei aio cp ever tae ise TR UN cd CU TD 12
Timex Sofware iio otia correa 95
Troiano SoftWare eiii id esse 94
Turner, Eley & Com:.........5..5... desa apro caede eó 38
USS SER «auper ee ceps dics e irr s ediley sa ni A 61
White, CRI 2L eee ori S eee nO atv DEus M daria 94
WISCONSHIC acia sis orion qna he TES aeria d c die 69
Wolfkámp-..... oeste ni aeter eese en ere FEDES IE 72
Woods, TOf 253. soos tra Aoi asi ci eae pd nete t 88
Yotk 10 AA editus epi dai LEN 45
Z Game soria irrita AS erid 95
Z Wariano aan 60
Zeta Software ....:. urere cs oes RAA sae PEC CRA Ta
LOOK esi AE A EE EAE N ET ER T 63
Zor Khan Industries ...........5 1 eee dax Sd es axe 59
ZX Panding....1. A ARR HARE RE eres 68
Ben SPRINTER A A IO ES Y 76
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SICAALJOS
DSICAADJCLI
THE PROWRITER COMETH.
(And It Cometh On Like Gangbusters./
Evolution.
It's inevitable. An eternal
verity.
Just when you think you've
got it knocked, and youre
resting on your laurels, some-
body comes along and makes
a dinosaur out of you.
Witness what happened to
the Centronics printer when
the Epson MX-80 came along
in 1981.
And now, witness what's
happening to the MX-80 as
the ProWriter cometh to be
the foremost printer of the
——— MÀ 3 decade.
SPEED
MX-80: 80 cps, for 46 full lines
per minute throughput.
PROWRITER: 120 cps, for
63 full lines per minute
throughput.
GRAPHICS
MX-80: Block graphics standard,
fine for things like bar graphs.
PROWRITER: High-resolu-
tion graphics features, fine
for bar graphs, smooth curves,
thin lines, intricate details, etc.
PRINTING
MX-80: Dot matrix business
quality.
PROWRITER: Dot matrix
correspondence quality, with
incremental pfinting capability
standard.
FEED
MX-80: Tractor feed standard;
optional friction-feed kit for
about $75 extra.
PROWRITER: Both tractor
and friction feed standard.
INTERFACE
MX-80: Parallel interface
standard; optional serial
interface for about $75 extra.
PROWRITER: Available stan-
dard— either parallel interface
or parallel/serial interface.
WARRANTY
MX-80: 90 days, from Epson.
PROWRITER: One full year,
from Leading Edge.
PRICE
Heh, heh.
Marketed Exclusively by Leading
Edge Products, Inc., 225 Turnpike
Street, Canton, Massachusetts
02021. Call: toll-free 1-800-345-6833;
or in Massachusetts call collect
(617) 828-8150. Telex 951-624.
LEADING
EDGE.
For a free poster of "Ace"
[Prowriter's pilot) doing his thing,
please write us.
.......-a
SSS
a E
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